MDU


Line plots across dimensions of each concept
Line plots across concepts
Tables

Table of contents



us-gaap:CommonStockValue
us-gaap:ConsolidatedEntities
us-gaap:StatementClassOfStock
us-gaap:PreferredStockParOrStatedValuePerShare

us-gaap:CommonStockSharesIssued
us-gaap:ConsolidatedEntities
us-gaap:StatementClassOfStock
us-gaap:StatementEquityComponents
us-gaap:StatementClassOfStock
us-gaap:CommonStockSharesAuthorized
us-gaap:StatementClassOfStock
us-gaap:PreferredStockSharesAuthorized

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:IncomeLossFromContinuingOperations
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeTaxExpenseBenefit
us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:IncomeTaxesPaidNet
us-gaap:StatementOperatingActivitiesSegment

us-gaap:InterestExpense
us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:InterestPaidNet

us-gaap:NetIncomeLoss
us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:OperatingExpenses

us-gaap:OperatingIncomeLoss
us-gaap:StatementBusinessSegments

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:StatementEquityComponents
us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount
us-gaap:OtherIncome

us-gaap:OtherNonoperatingIncomeExpense
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:Revenues
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus
us-gaap:ConsolidationItems, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:MajorCustomers
us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments
us-gaap:ProductOrService
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments, us-gaap:SubsegmentsConsolidationItems
us-gaap:SubsegmentsConsolidationItems

us-gaap:SellingGeneralAndAdministrativeExpense
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:Assets
us-gaap:ConsolidatedEntities
us-gaap:StatementBusinessSegments

us-gaap:LiabilitiesAndStockholdersEquity
us-gaap:ConsolidatedEntities

us-gaap:StockholdersEquity
us-gaap:ConsolidatedEntities
us-gaap:StatementEquityComponents

us-gaap:AssetsCurrent
us-gaap:ConsolidatedEntities

us-gaap:CashAndCashEquivalentsAtCarryingValue
us-gaap:ConsolidatedEntities

us-gaap:ReceivablesNetCurrent
us-gaap:ConsolidatedEntities

us-gaap:InventoryNet

us-gaap:InventoryFinishedGoods

us-gaap:InventoryRawMaterialsAndSupplies

us-gaap:OtherAssetsCurrent
us-gaap:ConsolidatedEntities

us-gaap:AssetsNoncurrent
us-gaap:ConsolidatedEntities

us-gaap:PropertyPlantAndEquipmentGross
us-gaap:PropertyPlantAndEquipmentByType, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AmortizationOfIntangibleAssets

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:LongTermInvestments
us-gaap:ConsolidatedEntities

us-gaap:Goodwill
us-gaap:BusinessAcquisition
us-gaap:StatementBusinessSegments

us-gaap:IntangibleAssetsNetExcludingGoodwill
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:OperatingLeaseRightOfUseAsset
us-gaap:ConsolidatedEntities

us-gaap:OtherAssetsNoncurrent
us-gaap:ConsolidatedEntities

us-gaap:AccountsPayableCurrent
us-gaap:ConsolidatedEntities

us-gaap:ContractWithCustomerLiabilityCurrent

us-gaap:DividendsPayableCurrent
us-gaap:ConsolidatedEntities

us-gaap:LiabilitiesCurrent
us-gaap:ConsolidatedEntities

us-gaap:LongTermDebtCurrent

us-gaap:OperatingLeaseLiabilityCurrent
us-gaap:ConsolidatedEntities

us-gaap:OtherLiabilitiesCurrent
us-gaap:ConsolidatedEntities

us-gaap:TaxesPayableCurrent
us-gaap:ConsolidatedEntities

us-gaap:LiabilitiesNoncurrent
us-gaap:ConsolidatedEntities

us-gaap:LongTermDebt
dei:LegalEntity, us-gaap:LongtermDebtType
us-gaap:FairValueByMeasurementBasis
us-gaap:LongtermDebtType

us-gaap:LongTermDebtNoncurrent

us-gaap:DeferredIncomeTaxLiabilitiesNet
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent
us-gaap:ConsolidatedEntities

us-gaap:OperatingLeaseLiabilityNoncurrent
us-gaap:ConsolidatedEntities

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:OperatingLeaseLiability

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:StockholdersEquity
us-gaap:ConsolidatedEntities
us-gaap:StatementEquityComponents

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
us-gaap:StatementEquityComponents

us-gaap:CommonStockValue
us-gaap:ConsolidatedEntities

us-gaap:AdditionalPaidInCapitalCommonStock
us-gaap:ConsolidatedEntities

us-gaap:RetainedEarningsAccumulatedDeficit
us-gaap:ConsolidatedEntities

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax
us-gaap:ConsolidatedEntities
us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount

us-gaap:StockIssuedDuringPeriodValueNewIssues
us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DepreciationDepletionAndAmortization

us-gaap:IncreaseDecreaseInAccountsPayable

us-gaap:IncreaseDecreaseInInventories

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss
us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:PaymentsToAcquireProductiveAssets

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:PaymentsOfDividends

us-gaap:PaymentsForRepurchaseOfCommonStock

us-gaap:DeferredTaxLiabilities

us-gaap:DeferredTaxAssetsValuationAllowance

mdu:ContractwithCustomerAssetNetCurrentChange

mdu:ContractwithCustomerAssetsandLiabilitiesNetChange

mdu:ContractwithCustomerLiabilityCurrentChange

mdu:ContractwithCustomerLiabilityNoncurrentChange
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanNetPeriodicBenefitCostAmountCapitalized
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanNetPeriodicBenefitCostIncludingAmountCapitalized
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
mdu:DepreciationAndAmortizationRatePercent
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
mdu:DepreciationAndAmortizationRequestedRateAmendedPercent
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmendedAmount
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmount
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
mdu:DepreciationAndAmortizationRequestedRatePercent

mdu:EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease
us-gaap:EnvironmentalRemediationSite
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:RenewableResourceCostAdjustmentRateTariff
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:TotalInfrastructureRider
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:TotalTransmissionCostAdjustmentRider
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:TransmissionCapitalProjectsIncreaseDecrease
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:TransmissionFormulaRevenueRequirement
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
mdu:UnderRecoveredBalanceTransmissionCostAdjustmentRider

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions
us-gaap:StatementEquityComponents

us-gaap:AllowanceForDoubtfulAccountsReceivableRecoveries
us-gaap:StatementBusinessSegments

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs
us-gaap:StatementBusinessSegments

us-gaap:CapitalExpendituresIncurredButNotYetPaid

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations

us-gaap:CommonStockDividendsPerShareDeclared

us-gaap:ContractWithCustomerLiabilityRevenueRecognized

us-gaap:ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanInterestCost
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanServiceCost

us-gaap:DividendsCommonStockCash
us-gaap:StatementEquityComponents

us-gaap:GoodwillPurchaseAccountingAdjustments
us-gaap:BusinessAcquisition
us-gaap:StatementBusinessSegments

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity

us-gaap:IncreaseDecreaseInOtherCurrentAssets

us-gaap:IncreaseDecreaseInOtherCurrentLiabilities

us-gaap:IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet

us-gaap:IncreaseDecreaseInReceivables

us-gaap:InterestCostsIncurredCapitalized

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations

us-gaap:NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1

us-gaap:OperatingLeaseLeaseIncome

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax
us-gaap:StatementEquityComponents
us-gaap:OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax

us-gaap:PaymentsForProceedsFromInvestments
us-gaap:StatementClassOfStock
us-gaap:PaymentsOfStockIssuanceCosts

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation
us-gaap:BusinessAcquisition
us-gaap:PaymentsToAcquireBusinessesGross

us-gaap:PaymentsToAcquireBusinessesNetOfCashAcquired

us-gaap:ProceedsFromIssuanceOfCommonStock
us-gaap:StatementClassOfStock

us-gaap:ProceedsFromSaleOfProductiveAssets

us-gaap:ProceedsFromShortTermDebt

us-gaap:ProvisionForDoubtfulAccounts
us-gaap:StatementBusinessSegments
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesApprovedRateIncreaseDecreaseAmount
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesApprovedRateIncreaseDecreasePercentage
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
us-gaap:PublicUtilitiesInterimRateIncreaseDecreaseAmount
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
us-gaap:PublicUtilitiesInterimRateIncreaseDecreasePercentage
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesRequestedRateIncreaseDecreaseAmendedAmount
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesRequestedRateIncreaseDecreaseAmendedPercentage
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesRequestedRateIncreaseDecreaseAmount
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesRequestedRateIncreaseDecreasePercentage
dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency
us-gaap:StatementEquityComponents
us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax

us-gaap:RepaymentsOfShortTermDebt

us-gaap:RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
us-gaap:StatementClassOfStock
us-gaap:StockIssuedDuringPeriodSharesNewIssues
us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents
us-gaap:StockIssuedDuringPeriodValueShareBasedCompensationGross

us-gaap:TaxesExcludingIncomeAndExciseTaxes
us-gaap:StatementEquityComponents
us-gaap:TreasuryStockRetiredCostMethodAmount
us-gaap:StatementEquityComponents
us-gaap:TreasuryStockSharesAcquired
us-gaap:StatementEquityComponents
us-gaap:TreasuryStockSharesRetired

us-gaap:TreasuryStockValueAcquiredCostMethod
us-gaap:StatementEquityComponents

us-gaap:UtilitiesOperatingExpenseGasAndPetroleumPurchased

us-gaap:UtilitiesOperatingExpensePurchasedPower

us-gaap:WeightedAverageNumberDilutedSharesOutstandingAdjustment

dei:EntityCommonStockSharesOutstanding

mdu:AggregatesHeldForResaleInventory

mdu:AmountOfSuretyBondsOutstanding

mdu:AsphaltOilInventory

mdu:CompanysExcludingItsSubsidiariesNetAssetsRestrictedFromUseForDividendPayments

mdu:ContractwithCustomerAssetsandLiabilitiesNet

mdu:DeferredTaxAssetsCustomerAdvances

mdu:DeferredTaxAssetsOperatingLeaseLiabilities

mdu:DeferredTaxAssetsPayrollTaxDeferral

mdu:DeferredTaxLiabilitiesOperatingLeaseRightofUseAssets

mdu:DeferredTaxliabilitiesPostretirementBenefits
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanAmountofRegulatoryAssetsorLiabilitiesbeforeTax
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnAssets
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanRegulatoryAssetsorLiabilitiesGainLossbeforeTax
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:DefinedBenefitPlanRegulatoryAssetsorLiabilitiesNetPriorServiceCostCreditBeforeTax

mdu:EnvironmentalMattersAccrualForRemedialInvestigationAndFeasibilityStudyCosts
us-gaap:EnvironmentalRemediationSite
mdu:EnvironmentalMattersAccrualForRemedialInvestigationandFeasibilityStudyCosts

mdu:EnvironmentalMattersAccrualForSiteRemediation
us-gaap:EnvironmentalRemediationSite
us-gaap:EnvironmentalRemediationSite
mdu:EnvironmentalMattersEstimatedCosts
us-gaap:EnvironmentalRemediationSite
mdu:EnvironmentalMattersInvestigativeCosts

mdu:FixedMaximumAmountsGuaranteedByYearFour

mdu:FixedMaximumAmountsGuaranteedByYearOne

mdu:FixedMaximumAmountsGuaranteedByYearThree

mdu:FixedMaximumAmountsGuaranteedByYearTwo

mdu:FixedMaximumAmountsGuaranteedThereafter
us-gaap:ConsolidatedEntities
mdu:InvestmentInSubsidiaries
us-gaap:IncomeTaxAuthority
mdu:InvestmentTaxCreditCarryforwardAmount
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanType
mdu:InvestmentsInNonqualifiedBenefitPlans
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanType
us-gaap:StatementClassOfStock
mdu:IssuanceCostsFromIssuanceOfCommonStockThroughTheATMProgram

mdu:LettersOfCredit

mdu:LettersOfCreditSetToExpireInTwoFiscalYears

mdu:LettersofCreditSettoExpireCurrentYear

mdu:LettersofCreditSettoExpireinNextFiscalYear

mdu:LettersofCreditSettoExpireinYear2

mdu:LossContingencyRegulated
dei:LegalEntity, us-gaap:CreditFacility, us-gaap:DebtInstrument
mdu:OptionToIncreaseBorrowingsMaximumAmount

mdu:PercentageInFixedIncomeAndOtherInvestments

mdu:PercentageInvestmentInCommonStockOfLargeCapCompanies

mdu:PercentageInvestmentInCommonStockOfMidCapCompanies

mdu:PercentageInvestmentInCommonStockOfSmallCapCompanies

mdu:PercentageInvestmentinCashandCashEquivalents

mdu:PercentageInvestmentinTargetDateInvestments
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:PostretirementInvestmentsInCollectiveAndMutualFunds
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
mdu:PostretirementInvestmentsInInsuranceContracts
dei:LegalEntity, us-gaap:LongtermDebtType
mdu:RatioOfFundedDebtToTotalCapitalizationAsSpecifiedInDebtConvenants
dei:LegalEntity, us-gaap:LongtermDebtType
mdu:RatioOfTotalDebtToTotalCapitalizationAsSpecifiedInDebtConvenants
dei:LegalEntity, us-gaap:ShortTermDebtType
dei:LegalEntity
mdu:RatioofTotalDebttoTotalCapitalization
us-gaap:ConsolidatedEntities
us-gaap:AccountsPayableRelatedPartiesCurrent

us-gaap:AccountsReceivableNoncurrent90DaysOrMorePastDueStillAccruing
us-gaap:ConsolidatedEntities
us-gaap:AccountsReceivableRelatedParties

us-gaap:AllowanceForDoubtfulAccountsReceivable
us-gaap:StatementBusinessSegments

us-gaap:AssetRetirementObligation
us-gaap:BusinessAcquisition

us-gaap:AssetRetirementObligationCurrent

us-gaap:AssetRetirementObligationsNoncurrent
us-gaap:FairValueByAssetClass, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:AssetsFairValueDisclosure
us-gaap:FairValueByAssetClass, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementFrequency

us-gaap:AvailableForSaleSecurities
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesAmortizedCost
us-gaap:FinancialInstrument
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationContingentConsiderationLiability
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
us-gaap:StatementClassOfStock
us-gaap:CommonStockCapitalSharesReservedForFutureIssuance

us-gaap:ConstructionContractorReceivableRetainage

us-gaap:ConstructionContractorReceivableRetainageAfterYearOne

us-gaap:ConstructionContractorReceivableRetainageYearOne

us-gaap:ContractWithCustomerAssetNet

us-gaap:ContractWithCustomerLiabilityNoncurrent
us-gaap:LongtermDebtType
us-gaap:DebtInstrumentUnamortizedDiscount
dei:LegalEntity, us-gaap:LongtermDebtType
us-gaap:DebtInstrumentUnusedBorrowingCapacityAmount
us-gaap:LongtermDebtType
us-gaap:DeferredFinanceCostsNet

us-gaap:DeferredGasCost
us-gaap:ConsolidatedEntities
us-gaap:DeferredIncomeTaxAssetsNet

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLegalSettlements

us-gaap:DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmountsRecognizedInBalanceSheet
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligation
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsInvestmentWithinPlanAssetCategoryAmount
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsInvestmentWithinPlanAssetCategoryPercentage
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
us-gaap:Range, us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanUltimateHealthCareCostTrendRate1

us-gaap:EmployeeRelatedLiabilitiesCurrent
us-gaap:ConsolidatedEntities

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized

us-gaap:EnergyRelatedInventoryNaturalGasInStorage

us-gaap:FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAccumulatedAmortization

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFive

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFour

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearThree

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsGross

us-gaap:GuaranteeObligationsMaximumExposure

us-gaap:InventoryGasInStorageUndergroundNoncurrent
us-gaap:JointlyOwnedUtilityPlant, us-gaap:PublicUtility
us-gaap:JointlyOwnedUtilityPlantGrossOwnershipAmountOfPlantInService
us-gaap:JointlyOwnedUtilityPlant, us-gaap:PublicUtility
us-gaap:JointlyOwnedUtilityPlantNetOwnershipAmount
us-gaap:JointlyOwnedUtilityPlant, us-gaap:PublicUtility
us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfConstructionWorkInProgress
us-gaap:JointlyOwnedUtilityPlant, us-gaap:PublicUtility
us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfPlantAccumulatedDepreciation
us-gaap:JointlyOwnedUtilityPlant, us-gaap:PublicUtility
us-gaap:JointlyOwnedUtilityPlantProportionateOwnershipShare

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths

us-gaap:LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths

us-gaap:LifeInsuranceCorporateOrBankOwnedAmount
dei:LegalEntity, us-gaap:CreditFacility, us-gaap:DebtInstrument
us-gaap:LineOfCredit
dei:LegalEntity, us-gaap:CreditFacility, us-gaap:DebtInstrument
us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity
us-gaap:FairValueByMeasurementBasis
us-gaap:LongTermDebtFairValue

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear
dei:LegalEntity, us-gaap:LongtermDebtType
us-gaap:LongtermDebtWeightedAverageInterestRate
us-gaap:LongtermDebtType

us-gaap:LossContingencyAccrualAtCarryingValue

us-gaap:LossContingencyReceivable

us-gaap:NetRegulatoryAssets

us-gaap:OperatingLeaseWeightedAverageDiscountRatePercent
us-gaap:IncomeTaxAuthority
us-gaap:OperatingLossCarryforwards

us-gaap:OtherInventoryNetOfReserves
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsAfterYearFive
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsNextTwelveMonths
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsYearFive1
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsYearFour1
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsYearThree1
us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType
us-gaap:PrescriptionDrugSubsidyReceiptsYearTwo1

us-gaap:RefundableGasCosts

us-gaap:RegulatoryAssets
us-gaap:RegulatoryAsset

us-gaap:RegulatoryAssetsCurrent
us-gaap:RegulatoryAsset

us-gaap:RegulatoryAssetsNoncurrent
us-gaap:RegulatoryAsset

us-gaap:RegulatoryLiabilities

us-gaap:RegulatoryLiabilityCurrent
us-gaap:RegulatoryLiability

us-gaap:RegulatoryLiabilityNoncurrent
us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount
us-gaap:RegulatoryLiability

us-gaap:RemainingAmountsOfRegulatoryAssetsForWhichNoReturnOnInvestmentDuringRecoveryPeriodIsProvided

us-gaap:RevenueRemainingPerformanceObligation
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
us-gaap:AwardDate, us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber

us-gaap:ShortTermBorrowings
dei:LegalEntity
dei:LegalEntity, us-gaap:ShortTermDebtType
us-gaap:IncomeTaxAuthority
us-gaap:TaxCreditCarryforwardAmount

us-gaap:UnbilledReceivablesCurrent

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFifthAnniversary

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary

us-gaap:UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears
us-gaap:ConsolidatedEntities
us-gaap:VariableInterestEntityEntityMaximumLossExposureAmount
us-gaap:InvestmentsByConsolidatedAndNonconsolidatedEntities

Plots across concepts


IncomeStatement
Other Comprehensive Income Loss Net Of Tax
Expenses
Other Nonoperating Income Expense
Balance Sheet
Intangible Assets Net Excluding Goodwill
Assets
Cash And Cash Equivalents At Carrying Value
Current Assets
Cash And Cash Equivalents At Carrying Value
NonCurrent Assets
Intangible Assets Net Excluding Goodwill
PropertyPlantAndEquipmentNet
Accumulated Depreciation Depletion And Amortization Property Plant And Equipment
Liabilities
Operating Lease Liability
Current Liabilities
Long Term Debt Current
Noncurrent Liabilities
Operating Lease Liability Noncurrent
Stockholders Equity
Accumulated Other Comprehensive Income Loss Net Of Tax
Per Share
Common Stock Dividends Per Share Declared
CashFlow
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInOperatingActivities
Increase Decrease In Inventories
NetCashProvidedByUsedInInvestingActivities
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInFinancingActivities
Repayments Of Long Term Debt
Shares
Weighted Average Number Of Shares Outstanding Basic
DividendsAndRepurchase
Payments For Repurchase Of Common Stock
OperatingLeaseLiability
Operating Lease Liability Current
LesseeOperatingLeaseLiabilityPaymentsDue
Lessee Operating Lease Liability Payments Due Year Four
InventoryNet
Inventory Finished Goods

Tables

  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:CommonStockValue █▇▇▇▇▇▇▇▆▆▅▅▅▅▅▅▅▅▅▅▅▅▅▅▄▄▄▄▄▃▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁202.822201.733201.061201.061201.061201.061200.923200.876199.539198.317196.565196.557196.557195.843195.843195.843195.843195.843195.843195.843195.843195.843195.805195.805195.411195.191194.755194.548194.139191.839189.869189.369189.369189.369189.369189.369189.369189.369189.332189.332189.332189.332188.901188.732188.673188.656
 us-gaap:PreferredStockParOrStatedValuePerShare us-gaap:StatementClassOfStock us-gaap:PreferredStockNANA0.0001NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CommonStockSharesIssued █▇▇▇▇▇▇▇▆▆▅▅▅▅▅▅▅▅▅▅▅▅▅▅▄▄▄▄▄▃▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁202.822301201.733458201.061198201.061198201.061198201.061198200.92279200.876334199.53911198.316808196.564907196.557245196.557245195.843297195.843297195.843297195.843297195.843297195.843297195.843297195.843297195.843297195.804665195.804665195.411301195.191129194.754812194.548389194.138654191.83872189.86878189.36945189.36945189.36945189.36945189.36945189.36945189.36945189.332485189.332485189.332485189.332485188.901379188.7322188.672532188.656012
 us-gaap:CommonStockSharesAuthorized us-gaap:StatementClassOfStock mdu:Atthemarketoffering▄▄▄6.46.46.4NANANA10.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:PreferredStockSharesAuthorized us-gaap:StatementClassOfStock us-gaap:PreferredStockNANA2.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding ███████████████████████████████████████▁▁▁█▁▁▁201.693200.952200.923200.619200.539200.456200.478199.383198.287196.414196.385196.265196.169195.982195.617195.783195.973196.023195.889195.811195.699195.284195.324195.169194.838194.479194.219194.3192.659190.432189.766189.638189.463189.222188.831188.831189.107189.182188.9320.1887970.1889680.188815188.3740.1883380.1882670.18822
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic ███████████████████████████████████████▁▁▁█▁▁▁201.345200.708200.522200.522200.522200.44200.383199.343198.27196.401196.023196.018195.524195.304195.304195.304195.304195.304195.304195.304195.304195.284195.266195.151194.805194.479194.136193.949192.06189.82188.929188.831188.831188.831188.831188.831188.831188.811188.7940.1887940.1887940.188671188.2810.188170.1881290.187963
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount NANANA0.0870.1870.068NA0.1550.00.064NA0.1140.00.0NA0.00.00.0NA0.00.00.0NA0.00.00.087NA0.00.00.0NA0.00.00.0NA0.4340.00.0NA0.00.00.0NANA0.0NA
us-gaap:EarningsPerShareBasic ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▄▆▇▄▂▁▇▇▇▇▇▇▆▇▅▅▇▆▇▇▆▆0.50.260.560.760.50.130.470.690.310.210.40.550.220.220.590.450.210.190.340.42-0.560.130.27-0.72-1.18-1.570.430.530.280.30.480.450.250.3-0.32-0.160.290.190.320.340.240.23NANANANA
us-gaap:EarningsPerShareDiluted ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▄▆▇▄▂▁▇▇▇▇▇▇▆▇▅▅▇▆▇▇▆▆0.50.260.560.760.50.130.470.690.310.210.40.550.220.220.590.450.210.190.330.42-0.560.130.27-0.72-1.18-1.570.430.530.280.30.480.440.240.3-0.32-0.160.290.190.320.340.240.23NANANANA
us-gaap:IncomeLossFromContinuingOperationsPerBasicShare ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▆▆▆▇▆▁▇▇▇▇▇▇▆▇▅▅▆▆▇▇▆▆▇▇▆▆5e-072.6e-075.6e-077.6e-075e-071.3e-074.6999999999999995e-076.800000000000001e-073.2e-072.1e-073.9e-075.5e-072.2e-072.2e-075.9e-074.6000000000000004e-072.2e-071.8e-073.4000000000000003e-074.5000000000000003e-072.4e-071.3e-072.4e-073.2e-071.1e-07-1.57e-064.2e-075.3e-072.8e-073e-074.8e-074.5000000000000003e-072.5e-073e-07-3.7e-07-1.6e-072.6e-071.9e-073.9e-073.4000000000000003e-072.4e-072.2e-074.9e-073.2e-072.6e-072.2e-07
us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▆▆▆▇▆▁▇▇▇▇▇▇▆▇▅▅▆▆▇▇▆▆▇▇▆▆5e-072.6e-075.6e-077.6e-075e-071.3e-074.6999999999999995e-076.800000000000001e-073.2e-072.1e-073.9e-075.5e-072.2e-072.2e-075.9e-074.6000000000000004e-072.2e-071.8e-073.3e-074.5000000000000003e-072.4e-071.3e-072.4e-073.2e-071.1e-07-1.57e-064.2e-075.3e-072.8e-073e-074.8e-074.4e-072.4e-073e-07-3.7e-07-1.6e-072.6e-071.9e-073.9e-073.4000000000000003e-072.4e-072.2e-074.9e-073.2e-072.6e-072.2e-07
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 Operating Margin us-gaap:StatementBusinessSegments mdu:ConstructionMaterialsAndContracting▅▂▄▇▅▂▄█▅▁▄▇▄▁633.674265.659471.956822.439621.045262.144497.364869.376595.799227.113458.75743.763509.388213.284NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments mdu:ConstructionServices▇▇▇█▆▇▆▆▅▄▃▁▁▁524.744517.47531.468550.608496.405512.205482.591478.381464.192420.733383.123329.578323.02334.05NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments mdu:Electric▄▅▃▆▁▅▆▇▃█▄▅▂▆83.6584.67381.74587.44776.43885.90888.30289.84581.01192.56683.13986.0878.49987.404NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments mdu:NaturalGasDistribution▃█▆▁▂▇▇▁▂█▆▁▂█153.788350.206285.0194.703141.494326.443295.56693.642133.867342.147268.79592.248129.54332.664NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments mdu:Pipeline█▁27.7739.913NA32.06827.65810.655NA32.533NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments us-gaap:CorporateAndOther▆▅▅▆▁▆▆▆▆▆▅▇█▇0.0280.0170.0150.024-0.1120.0180.0250.0220.0240.0190.0140.0470.090.058NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 SG&A Ratio us-gaap:PublicUtilityRegulatedOrUnregulatedStatus us-gaap:RegulatedOperation▃█▆▁▂▇▇▁▂█▆▁▂▇▆▁260.568442.381378.995210.115241.353418.682393.995209.444236.247439.617361.466200.617226.684424.459378.724206.936NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 SG&A Ratio us-gaap:PublicUtilityRegulatedOrUnregulatedStatus us-gaap:UnregulatedOperation▆▃▅█▆▃▅█▅▂▄▅▃▁▃▅1163.089785.5571006.1641377.1741121.575778.691984.2181354.3551067.326651.574848.4081080.17837.913551.834786.5151065.612NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 TTM Greenblatt ROC _ _▇▇▇█▇▆▇█▇▇▇▇▇▇▇█▇▇▇▇▇▆▆▇▆▁▇█▇▇▇▇▇▇▅▆▇▇▇▇▇▇▇137.68985.164145.89203.711138.25457.07130.221189.4797.31164.218118.351140.00473.99269.376125.544156.37779.67967.112111.486146.68488.96541.75255.393109.74345.328-474.347109.622176.76598.934102.904147.117149.87391.378104.531-109.529-34.03591.71471.057126.577119.42182.30378.066130.174NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:ComprehensiveIncomeNetOfTax ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▄▆▆▄▂▁▇▇▆▇▇▇▆▆▅▅▇▆▆▇▇▆▇▇▆100.73252.699104.465153.638100.28925.83789.641138.04962.30341.784.105107.76744.52742.87113.31987.79941.61136.87367.88883.301-108.77723.43555.23-139.046-228.926-304.73879.184103.37554.44657.329110.18184.3446.30648.621-63.26-46.54477.46829.86114.59495.65465.91121.12657.18361.96947.84NA
us-gaap:IncomeLossFromContinuingOperations ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▆▆▆▆▆▁▇▇▆▇▇▇▆▇▅▅▆▆▇▇▆▆▇▇▆▆100.17152.116112.131153.01599.84225.53994.804136.12863.14541.08975.982107.36944.07541.96115.39489.54944.40535.63866.54788.38646.29814.66432.07753.414.057-309.44580.079102.11852.7856.18491.34884.5546.39256.592-69.686-29.53249.00735.8974.08864.145.23542.52992.361.0148.93841.772
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest ▇▇▇█▇▆▇█▇▇▇▇▇▇▇█▇▇▇▇▇▆▇▇▆▁▇█▇▇▇▇▇▇▅▆▇▇▇▇▇▇123.33565.065135.544184.562123.49931.512109.317167.22673.49748.40690.837121.73254.79149.511106.028136.47959.69547.82692.297126.14767.61819.22245.15990.29523.858-495.17290.23156.88779.89884.116128.525131.12671.3884.588-125.349-49.78575.69853.969110.729101.9465.12458.433NANANANA
us-gaap:IncomeTaxExpenseBenefit ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▆█▇▇▇█▇▇▇▇▇▁▇█▇▇▇█▇▇▅▆▇▇▇█▇▇█▇▇▇23.16412.94923.41231.54723.6575.97314.51331.09810.3527.31714.85614.36310.7167.551-9.36546.9315.2912.18825.75137.76121.324.55813.08336.8959.801-185.72710.15154.76927.11827.93237.17746.57624.98827.996-55.662-20.25326.69118.07936.64237.8419.88915.90441.74731.27624.1825.326
us-gaap:IncomeTaxesPaidNet ▅▄▅▆▃▃▂▃▃▃▃▃▃▃█▄▆▃▅▆▅▃▄▄▃▃▅▃▅▄▂▅▃▂▃▃▃▃▃▁▃▄▄▃32.85413.8822.08842.7130.736-0.001-10.291-2.3084.0950.0297.1544.8535.09-1.05665.70714.04235.15-2.76232.13743.8831.32-1.42912.75717.5354.456-1.33924.9214.18230.5499.435-5.40532.9114.597-7.2460.0670.7922.1330.285-0.956-24.2182.9069.9819.930.951NANA
us-gaap:InterestExpense ▆▆▆▆▇▇▇██▆▅▄▄▄▄▄▄▃▄▅▅▇▆▆▇▆▅▅▄▄▄▄▄▄▃▃▁▃▃▃▃▅▄▄▄▄23.38123.45323.38723.76124.81824.55324.49325.25825.42923.40722.41220.95520.820.44720.8120.90920.76620.30320.48322.27822.21923.77623.20422.94623.7923.14922.10422.42521.51620.97120.60521.01221.42720.87419.7719.8417.6519.43919.71219.58920.03622.01721.06120.94420.4920.516
us-gaap:InterestPaidNet █▁▆▂█▂▇▃▆▃▅▃▄▃▄▃▄▃▄▄▄▅▄▅▄▅▃▄▃▄▄▃▃▄▂▄▁▄▁▅▂▆▂▆31.56714.30325.59515.31731.79115.97828.81818.89426.63519.06724.6518.89221.55717.9121.51918.91221.66117.54621.63921.42121.0323.8320.18325.10121.22823.87419.66122.24918.59120.8521.40818.84119.58321.85716.42222.06313.4622.43314.46423.02315.06725.57915.2526.06NANA
us-gaap:NetIncomeLoss ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▄▆▆▄▂▁▇▇▆▇▇▇▆▇▅▅▆▆▇▇▆▆▇▇▆▆100.1952.131112.294153.07899.70325.1395.065137.63761.82540.92678.828107.25143.80242.437115.31287.35141.21537.32565.73182.986-109.15324.86952.534-139.448-229.604-305.91784.256103.20954.10656.66291.4584.45646.51256.515-60.986-29.67154.11335.7961.00863.97445.06742.97788.93961.0148.93841.772
us-gaap:OperatingExpenses ▇▅▆█▆▅▆█▆▄▅▅▄▃▄▅▄▂▃▄▃▂▄▆▃█▄▆▄▃▄▅▃▂▆▆▂▁▃▄▂▂▃▄▂▁1285.9681142.7741239.271383.5781224.6741140.3031247.9921374.3291206.2621026.9731091.5241140.783990.605906.9171039.6951116.171987.96870.813904.6131061.883954.983863.4011007.0921170.757940.8871392.8571053.5821193.69995.112939.9491037.3061135.909969.217827.0731190.6731207.553876.248781.75939.1721032.76848.454823.739912.3771016.961817.782751.848
us-gaap:OperatingIncomeLoss ▇▇▇█▇▆▇█▇▇▇▇▇▇▇█▇▇▇▇▇▆▆▇▆▁▇█▇▇▇▇▇▇▅▆▇▇▇▇▇▇▇▇▇▇137.68985.164145.89203.711138.25457.07130.221189.4797.31164.218118.351140.00473.99269.376125.544156.37779.67967.112111.486146.68488.96541.75255.393109.74345.328-474.347109.622176.76598.934102.904147.117149.87391.378104.531-109.529-34.03591.71471.057126.577119.42182.30378.066130.174108.96288.66282.929
us-gaap:OtherComprehensiveIncomeLossNetOfTax ▅▅▄▅▅▅▅▅▅▅▆▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▇▅▅▄▅▄▇▅▁█▇0.5420.568-7.8290.560.5860.707-5.4240.4120.4780.7745.2770.5160.7250.433-1.9930.4480.396-0.4522.1580.3150.376-1.4342.6960.4020.6781.179-5.0710.1660.340.66718.732-0.116-0.206-7.894-2.273-16.87323.355-5.929-46.41331.6820.844NANANANANA
 us-gaap:OtherIncome us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount srt:RestatementAdjustmentNANA6.5NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherNonoperatingIncomeExpense ▆▄█▅▇▃▄▄▄▆▁▄▄▃▃▃▃▃▃▄▃▃█▄▄▄▄▄▄▄▄▄▄▃▄▄▃▃▄▃▄▄▃▄▄▄9.0273.35413.0424.61210.063-1.0053.593.0141.6157.595-5.1022.6831.5990.5821.2941.0110.7821.0171.2941.7410.8721.24612.9713.4982.322.3242.412.6442.7772.1321.7652.3261.4361.2422.5921.7021.2491.0981.431.2821.9081.91.0891.742.6862.502
us-gaap:Revenues ▆▅▆█▆▄▆█▅▃▄▅▃▂▄▅▃▂▃▄▃▂▃▅▂▂▄▆▃▃▄▅▃▂▃▄▂▁▃▄▂▂▃▄▂▁1423.6571227.9381385.161587.2891362.9281197.3731378.2131563.7991303.5731091.1911209.8751280.7871064.597976.2931165.2391272.5481067.639937.9251016.0991208.5671043.948905.1531062.4851280.5986.215918.511163.2041370.4551094.0461042.8531184.4231285.7821060.595931.6041081.1441173.518967.962852.8071065.7491152.181930.757901.8051042.5511125.923906.444834.777
us-gaap:SellingGeneralAndAdministrativeExpense ▆▃▅█▆▄▅█▆▂▄▆▄▁▃▅1077.796811.659964.0731214.0191029.171821.0958.731212.621021.031702.914836.59996.591822.084600.856781.01973.966NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:Assets █▇▇▇▇▇▆▆▆▅▄▃▃▂▂▂▂▂▂▂▂▃▃▄▅▅▇▆▆▅▄▅▄▄▃▄▄▃▃▂▂▂▂▂▁▁8298.2118069.2758053.3728125.4997911.1327850.5167683.0597730.6117591.4937278.9236988.116718.1936533.976348.8526334.6666344.4456230.4986148.4586284.4676353.2066389.5846618.46627.6086985.3197270.0557317.3857809.9787774.0947668.3177408.8497061.3327167.1087091.6716828.1826682.4916902.6716901.576538.6316556.1256359.9536257.3816191.2916303.5496216.9556112.8065981.847
us-gaap:LiabilitiesAndStockholdersEquity █▇▇▇▇▇▆▆▆▅▄▃▃▂▂▂▂▂▂▂▂▃▃▄▅▅▇▆▆▅▄▅▄▄▃▄▄▃▃▂▂▂▂▂▁▁8298.2118069.2758053.3728125.4997911.1327850.5167683.0597730.6117591.4937278.9236988.116718.1936533.976348.8526334.6666344.4456230.4986148.4586284.4676353.2066389.5846618.46627.6086985.3197270.0557317.3857809.9787774.0947668.3177408.8497061.3327167.1087091.6716828.1826682.4916902.6716901.576538.6316556.1256359.9536257.3816191.2916303.5496216.9556112.8065981.847
us-gaap:StockholdersEquity █▇▇▇▆▅▅▅▄▄▃▃▃▂▂▂▁▂▂▁▁▂▂▂▃▅█▇▇▆▅▅▄▄▄▅▅▅▅▅▅▄▄▄▄▄3198.8023100.3063079.1053012.7652897.6872836.5922847.2462795.6062660.3012605.6922566.7752521.2932451.0782426.1112429.0432353.9172302.9522313.9052316.2442285.0612237.612382.3812396.5052376.6312542.9312801.7283134.0413083.2553000.5062901.5882823.1642731.5932678.722663.8822648.2482742.932820.2722773.5982775.5672791.0792725.352689.0832692.8022662.1212627.742608.02
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AssetsCurrent ▇▆▆█▇▆▅▇▇▅▄▄▃▂▃▃▂▁▁▄▄▂▂▄▅▄▄▇▅▄▃▅▅▄▃▅▅▃▄▃▃▃▄▂▁▂1461.9451323.2741337.3471502.5571396.771373.3881297.7011461.8151444.811235.2291184.1321214.0451116.1921040.8141069.9951099.2421015.97942.073977.4751144.6251157.5031054.9361021.0421196.6441282.7641161.5461194.9731417.6721276.2061204.531116.6881254.971292.2471149.2341128.0811249.41233.8241078.1531194.6381132.0181071.0311064.0031167.1681035.523969.299989.761
us-gaap:CashAndCashEquivalentsAtCarryingValue ▂▂▂▂▂▄▂▂▂▂▂▂▁▂▁▁▁▂▁▂▃▃▃▃▅▄▃█▃▃▁▂▄▂▂▂▃▃▆▄▄▅█▁▂▄57.94655.09459.54766.0764.358116.52666.45967.071.96649.72153.94867.07741.65958.76434.59937.35640.04850.73546.10759.86885.11790.93884.59188.63144.372122.24181.855233.67690.31883.745.22566.174114.97174.14949.04274.242101.64391.389162.772118.702107.768136.016222.07436.28565.792106.664
us-gaap:ReceivablesNetCurrent ▇▅▆█▇▆▆▇▆▄▄▅▅▄▄▅▄▂▃▄▃▂▃▄▃▂▄▅▄▄▄▅▄▃▄▅▃▂▃▃▂▂▂▃▁▁903.831784.582873.9861009.433920.824835.468836.605968.279890.579722.152722.945787.344743.687664.319727.03739.402661.771554.185630.243665.142637.166537.744590.105677.928627.169564.09693.318784.028731.247690.761713.067787.311734.765635.564678.123743.274654.609539.589646.251641.389566.366533.279583.743585.487502.454467.79
us-gaap:InventoryNet ▆▆▅▄▅▆▄▄▇▆▅▄▄▃▁▁▂▂▂▂▃▄▃▃▆▇▅▅▇▅▄▆█▇▆▆▇▆▄▄▄▃▃▃▃▃316.328316.737291.167286.223302.837305.958278.407286.057325.944311.535287.309270.293278.239257.792226.583232.555249.87250.609238.273245.79265.849276.812253.727258.341314.405336.598300.811302.705331.422301.332282.391314.571345.885334.872317.415315.767333.392313.341274.205269.569277.327262.696252.897261.68260.163253.931
us-gaap:InventoryFinishedGoods ▆▅▃▄▄▄▄▄▆▅▄▁▂▂▁▁▁▂▂▁▂▂▁▁▁▁▅▅▅▄▄▄▆▅▇▇▇▆█▇█▇▇26.87124.31921.08721.52522.97423.10922.23223.90227.16725.10422.55215.95417.50216.37814.90515.34616.16416.54616.43715.67218.43917.44115.31815.56316.1415.68824.4224.56625.50722.46321.7223.71327.3324.34231.17230.82730.41728.45932.16530.97433.43531.8330.182NANANA
us-gaap:InventoryRawMaterialsAndSupplies ▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▂▂▁▁▁▂▁▁▂▇▇▇▇▇▇▇██▇██▇▆▇▇▆▆27.96926.48125.14226.60927.80526.29322.51225.69628.74626.44123.61123.56324.68819.49318.6520.77822.65722.07418.37218.58420.76521.64516.99719.40422.59465.59965.68371.51570.93868.80969.80871.3774.64875.86869.3975.55172.32168.36961.61164.98865.36361.78857.324NANANA
us-gaap:OtherAssetsCurrent ▃▃▂▃▂▂▆▇██▆▄▂▂▄▄▃▄▂▂▂▂▁▂▄▅▃▃▄▅▂▂▂▃▁▃▄74.25968.40944.1261.70648.19460.23115.805140.053155.893151.391119.588.7652.03559.48181.30489.62563.95379.25448.46149.08150.30957.82135.18956.60481.35598.50376.84872.993.9899.22949.5156.25758.8768.82842.35171.57985.729NANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AssetsNoncurrent ██████▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▂▂6836.2666746.0016716.0256622.9426514.3626477.1281319.561322.5531278.5571255.6961086.6811054.5341059.9691052.1041047.871120.1791129.5181142.6021249.7991077.6541176.3071487.0291559.6581898.425NANANANANANANANANANANANANANANANANANANANANANA
us-gaap:PropertyPlantAndEquipmentGross ▅▅▅▅▄▄▄▄▃▃▃▂▂▂▂▁▁▁▁▁▁▂▂▁▁▇█▇▇▇▆▆▅▅▅▅▄▄▃▃▃▃▃▂▂▂8417.5598288.8798300.778203.7518063.4358008.3387908.6287746.7547625.6547502.3687397.3217102.966975.9196842.9676770.8296658.8916591.3826544.0776510.2296588.4456526.5636878.5956817.6686627.2696556.0589299.7139693.1719438.6099390.5389150.2698803.8668651.3348454.2048303.0658107.7518129.8728068.1777798.777646.2227506.8337394.6167271.1737218.5037163.5157085.6326875.397
us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment ▄▄▄▄▃▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁██▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▃▃▃3129.7173096.3713133.8313115.8053064.8333039.8122991.4862944.9282903.2742858.9862818.6442796.6492758.1632725.4842691.6412667.7622638.0982609.3032578.9022583.5662551.9412543.9422506.5712455.4022444.1344233.1934166.4074092.0174011.8583954.4423872.4873796.0523709.6793678.5353608.9123546.9273478.1183419.5743361.2083307.4333236.4173174.6543103.3233056.1273000.6632935.453
us-gaap:AmortizationOfIntangibleAssets ▄▄▇▆█▆▂▂▂▂▁▁▁▁▁▂▂▂▂▂▂▂▂▂▂▂▂▂▃▂▃▄▃▂▃▃▃▃▂▃▃▃▂▄▃1.21.52.22.12.72.00.80.50.50.60.30.30.30.40.30.50.60.60.60.60.60.60.50.60.70.70.70.71.00.81.01.21.00.80.91.01.00.90.71.11.00.90.81.31.1NA
us-gaap:PropertyPlantAndEquipmentNet ▇▇▆▆▆▆▅▅▄▄▄▃▂▂▂▁▁▁▁▁▁▃▃▂▂▆█▇▇▇▅▅▅▄▃▄▄▃▃▂▂▂▂▂▂▁5287.8425192.5085166.9395087.9464998.6024968.5264917.1424801.8264722.384643.3824578.6774306.3114217.7564117.4834079.1883991.1293953.2843934.7743931.3274004.8793974.6224334.6534311.0974171.8674111.9245066.525526.7645346.5925378.685195.8274931.3794855.2824744.5254624.534498.8394582.9454590.0594379.1964285.0144199.44158.1994096.5194115.184107.3884084.9693939.944
us-gaap:LongTermInvestments █▇▇▇▆▅▆▅▅▅▅▅▅▅▅▄▄▄▄▄▃▃▃▃▃▃▃▃▃▂▂▂▂▂▁▁▁▂▂▂▃▃173.157167.741165.022158.44154.779145.237148.656144.417145.746144.616138.62143.303140.053138.451137.613133.895131.726129.009125.866126.048124.531121.955119.704118.063119.446118.407117.92115.656116.594113.763112.939108.664106.508106.846103.243102.13999.343113.799109.424109.249116.368117.015NANANANA
us-gaap:Goodwill ████▇█▅▅▅▅▄▂▂▁▁▁▁▁▁▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁717.863714.963714.963712.677708.664713.527681.358681.349679.395679.395664.922640.203642.374631.791631.791631.791631.791631.791631.791641.527641.527641.527635.204635.204635.204635.204635.204636.039636.039636.039636.039636.039636.039636.039636.039636.039635.389635.389634.931634.931634.931634.931634.633634.633634.654634.633
us-gaap:IntangibleAssetsNetExcludingGoodwill ▆▆▆▆▇█▄▄▃▃▃▁▁▁▁▁▁▁▂▂▂▂▂▂▂▂▂▃▃▃▃▃▄▄▄▄▄▅▅▅▆▆▆▆▆▆23.40123.96125.49626.37631.51534.2515.24615.51111.32311.6810.8154.3184.193.4653.8374.2094.7855.3475.9256.5297.167.8037.3427.9088.5069.1669.8410.59611.26612.29613.09914.09215.31216.31817.12918.01518.65619.99120.84322.24823.33724.35125.27126.11226.19926.612
us-gaap:OperatingLeaseRightOfUseAsset █████████▇▁112.437116.663120.113120.534115.751114.382115.323118.764118.795107.4860.0NA0.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherAssetsNoncurrent ▁▁▁▁▁▁██▇▇▆▆▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▃▃▃▃▄▄▄▄▄▄▄▄▃▃▃▃▃▃▃144.653150.248144.111147.205154.026153.017506.207504.842466.957455.048408.857408.178409.407412.456407.85419.846416.759409.745415.419360.537360.52359.977366.485355.72362.407326.542325.277247.539249.532246.394251.188298.061297.04295.215299.16314.133324.299312.103311.275262.107253.515254.472257.636260.722255.473249.454
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AccountsPayableCurrent █▆███▆▇▆▅▅▅▅▄▂▄▃▂▁▂▂▂▂▄▃▂▂▆▇█▇▇█▇▆▆▇▆▄▄▃▃▂▃431.878379.348426.264436.718433.362384.339403.391378.37356.059352.18358.505339.713330.926267.994312.327304.101279.211239.013279.962281.373275.791260.432310.466292.612272.988259.881382.671410.382424.201399.935404.961437.74411.621375.942388.015402.241379.84321.369337.228305.695304.049267.922301.132NANANA
us-gaap:ContractWithCustomerLiabilityCurrent ▇▇████▇▅▂▂▃▃▃▂▁146.116142.828158.603158.923158.272153.23142.768120.20790.03186.03193.90198.4790.47880.90571.479NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:DividendsPayableCurrent ██████████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▆▆▆▁▆▆▆▆▆▆▆▆42.79142.7442.61141.60841.60841.60841.5840.4640.22539.87539.69538.71438.71438.57338.57337.59637.59637.76737.76736.79136.79136.79136.78435.80735.73435.68735.60734.60734.38833.9833.73732.74532.74532.7440.17131.831.831.831.79430.8530.8530.8530.773NANANA
us-gaap:LiabilitiesCurrent ▆▅▆█▇▄▅▇▅█▇▃▄▃▄▅▂▁▂▃▂▃▆▆█▇▆▆▄▃▄▄▅▆▅▇▇▅▅▃▃▂▃▃▁▂944.36900.037963.5221066.99999.719824.479866.4271033.677912.6021062.779986.05725.218800.984764.261812.858856.568693.805618.034669.659744.202702.377761.467947.639941.6781080.265986.865968.694938.527796.664745.478784.9845.807865.889917.183850.1151025.1451024.491910.221898.753764.449723.419654.77768.076727.177640.693662.913
us-gaap:LongTermDebtCurrent ▁▁▁▁▁▁▁▃▂██▁▄▅▅▅▃▂▂▄▃▄█1.5491.5521.5551.55816.5616.5616.5465.8151.822251.846251.8543.915109.199149.199148.499148.49983.49943.49943.59893.59858.59898.54238.539NANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OperatingLeaseLiabilityCurrent █████▇███▇▁31.78732.56233.65533.7731.98531.14131.66432.58431.61530.9780.0NA0.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesCurrent ▃▄▄▆▃▂▅▆▅▅▅▅▅▄▃▃▃▃▃▃▄▃▂▁▁▃▂▂▂▃▂▂▃▄▄▆▇██▆▆▆▅188.187201.246198.514226.863182.597172.561221.502225.925218.442213.541221.059221.62208.696204.328186.01184.58181.03188.373184.377191.904196.701189.275171.592157.65164.675179.672172.561173.247179.402185.287171.106171.42185.389205.394204.698233.773244.922255.172259.32226.986224.22227.088222.639NANANA
us-gaap:TaxesPayableCurrent ▅▆▆▇▅▃▂▂▂▃▁▂▂▃▁█▃▅▂▃▂▂▂▂▁▂▂█▂▃▅▅▆▃▂▃▂▂▄▅▂▂▃78.80588.71188.84496.70880.88258.74348.9753.50546.73155.31941.92950.46147.80357.35442.537108.94655.03774.63848.16459.74745.74950.22245.77544.26738.96648.43645.631105.02748.98561.84774.17580.39289.89655.74846.47554.90346.91951.01970.17677.1945.06549.85256.186NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:LiabilitiesNoncurrent ██████▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁4155.0494068.9324010.7454045.7444013.7264189.4451742.8191720.3821690.6061664.2711578.4441560.1271538.1971528.1371526.4111541.9071555.7641557.0121552.0031515.5931520.8881539.411531.9781516.3291544.6351615.3831766.2221615.6081662.3321619.9621578.2441602.9391593.4771617.4481573.2611632.1831673.3751640.8381596.3941457.4111439.0781433.3611408.7161390.4861335.6591284.768
us-gaap:LongTermDebt ▆▄▃▄▄█▄▄▆▃▁2337.0492253.2742213.132270.292281.8762455.2352243.1072246.7562379.8062198.0272108.695NANANA1714.853NANANA1790.159NANANA1796.163NANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LongTermDebtNoncurrent ▇▇▆▇▇█▆▆▇▄▃▄▂▂▁▁▂▂▃▃▄▃▁2335.52251.7222211.5752268.7322265.3162438.6752226.5672180.9462327.9841946.1811856.8411911.5551743.7111630.3431566.3541592.0531677.9771659.5071746.5611808.351928.7091759.5141557.624NANANANANANANANANANANANANANANA1285.411NANANA1433.955NANANA
us-gaap:DeferredIncomeTaxLiabilitiesNet ▅▅▅▅▅▅▄▄▃▃▃▂▁▁▁██████538.633528.551516.098533.524516.76515.711506.583487.194457.588444.965430.085405.761362.896346.218347.271652.413668.239666.905668.226662.326666.601NANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent us-gaap:RetirementPlanFundingStatus,us-gaap:RetirementPlanTaxStatus,us-gaap:RetirementPlanType us-gaap:OverfundedPlan,us-gaap:QualifiedPlan,us-gaap:OtherPostretirementBenefitPlansDefinedBenefitNANA20.663NANANA18.855NANANA18.868NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent us-gaap:RetirementPlanFundingStatus,us-gaap:RetirementPlanTaxStatus,us-gaap:RetirementPlanType us-gaap:UnderfundedPlan,us-gaap:QualifiedPlan,us-gaap:PensionPlansDefinedBenefitNANA53.526NANANA55.902NANANA83.793NANANA91.539NANANA102.798NANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesNoncurrent ▁▁▁▁▁▁█████████▆▆▆▆▅▅▅▅▅▅▅▅▄▅▄▄▅▅▅▅▅▅▅▅▄▄▄▅▄▄▄320.777329.935327.773295.845286.527290.9711152.4941147.0221145.8461142.8621148.3591154.3661175.3011181.9191179.14889.494887.525890.107883.777821.889820.349811.106811.659755.107755.742810.626813.809727.801736.519720.542718.938794.928810.639814.643818.159834.934833.692842.169827.228710.465711.516731.428736.447718.331708.403680.965
us-gaap:OperatingLeaseLiabilityNoncurrent █████████▇▁81.05284.49486.86887.1484.30283.41483.74286.16687.17276.4440.0NA0.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo NANA25.133NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree NANA16.639NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour NANA12.14NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive NANA7.852NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive NANA48.845NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:StockholdersEquity █▇▇▇▆▅▅▅▄▄▃▃▃▂▂▂▁▂▂▁▁▂▂▂▃▅█▇▇▆▅▅▄▄▄▅▅▅▅▅▅▄▄▄▄▄3198.8023100.3063079.1053012.7652897.6872836.5922847.2462795.6062660.3012605.6922566.7752521.2932451.0782426.1112429.0432353.9172302.9522313.9052316.2442285.0612237.612382.3812396.5052376.6312542.9312801.7283134.0413083.2553000.5062901.5882823.1642731.5932678.722663.8822648.2482742.932820.2722773.5982775.5672791.0792725.352689.0832692.8022662.1212627.742608.02
us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest NANA3079.105NANANA2847.246NANANA2566.7752521.2932451.0782426.1112429.0432353.9172302.9522313.9052316.2442285.0612237.612495.3842520.5482514.8712686.8922934.4433249.7843158.5033064.4422949.8042855.9022750.492694.6422674.9822648.2482742.932820.2722773.5982775.567NANANA2692.802NANANA
 us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap:StatementEquityComponents us-gaap:AccumulatedOtherComprehensiveIncomeNANA-48.078NANANA-42.102NANANA-38.342-43.619-44.135-44.86-37.334-35.341-35.789-36.185-35.733-37.891-38.206-38.582-37.148-39.844-40.246-40.924-42.103-37.032-37.198NA-38.205NANANA-48.721NANANA-47.001NANANA-31.261NANANA
 us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapitalNANA1371.385NANANA1355.404NANANA1248.5761247.1511245.8581227.2851233.4121232.7661231.8921231.1711232.478NANANA1230.119NANANA1207.188NANANA1056.996NANANA1039.08NANANA1035.739NANANA1026.349NANANA
 us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap:StatementEquityComponents us-gaap:CommonStockNANA201.061NANANA200.923NANANA196.565196.557196.557195.843195.843195.843195.843195.843195.843NANANA195.805NANANA194.755NANANA189.869NANANA189.369NANANA189.332NANANA188.901NANANA
 us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap:StatementEquityComponents us-gaap:RetainedEarningsNANA1558.363NANANA1336.647NANANA1163.6021124.831056.4241051.4691040.748964.275914.632911.702912.282NANANA996.355NANANA1762.827NANANA1603.13NANANA1457.146NANANA1586.123NANANA1497.439NANANA
us-gaap:CommonStockValue █▇▇▇▇▇▇▇▆▆▅▅▅▅▅▅▅▅▅▅▅▅▅▅▄▄▄▄▄▃▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁202.822201.733201.061201.061201.061201.061200.923200.876199.539198.317196.565196.557196.557195.843195.843195.843195.843195.843195.843195.843195.843195.843195.805195.805195.411195.191194.755194.548194.139191.839189.869189.369189.369189.369189.369189.369189.369189.369189.332189.332189.332189.332188.901188.732188.673188.656
us-gaap:AdditionalPaidInCapitalCommonStock █▇▇▇▇▇▇▇▆▆▅▅▅▄▅▅▅▅▅▅▅▅▅▅▄▄▄▄▄▂▁▁▁▁▁▁▁▁▁▁▁1422.1691382.1581371.3851366.4941363.1821360.5641355.4041351.991315.5111284.061248.5761247.1511245.8581227.2851233.4121232.7661231.8921231.1711232.4781231.3961230.3421229.4311230.1191228.8751220.6151214.8671207.1881200.5911186.91110.2211056.9961041.7871040.3791038.971039.081038.0661036.9351035.81035.7391034.4111033.366NANANANANA
us-gaap:RetainedEarningsAccumulatedDeficit ▇▇▆▆▅▅▅▄▄▃▃▃▃▃▃▂▂▂▂▁▁▂▂▂▃▅██▇▇▇▆▆▆▆▆▇▇▇▆▆▆▆▆▅▅1624.4051567.5511558.3631489.0851377.8791319.9881336.6471283.0441185.9671164.5091163.6021124.831056.4241051.4691040.748964.275914.632911.702912.282884.339838.257984.315996.355980.4211155.7771421.221762.8271713.7741645.2911625.6921603.131546.01494.4191480.7841457.1461550.5691612.1691589.9851586.1231556.551523.5461509.4491497.4391439.051407.951388.914
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▂▂▂▃▃▃▃▃▃▃▃▃▃▂▃▄▄▄▄▃▃▃▃▃▃▃▃▃▃▃▃▁▁▁▂▂▄▁▂█▄▁▄███-46.968-47.51-48.078-40.249-40.809-41.395-42.102-36.678-37.09-37.568-38.342-43.619-44.135-44.86-37.334-35.341-35.789-36.185-35.733-37.891-38.206-38.582-37.148-39.844-40.246-40.924-42.103-37.032-37.198-37.538-38.205-56.937-56.821-56.615-48.721-46.448-29.575-52.93-47.001-0.588-32.268-53.112-31.2610.496-0.4630.635
 us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap:ConsolidatedEntities srt:ParentCompanyNANA-48.078NANANA-42.102NANANA-38.342NANANA-37.334NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount srt:RestatementAdjustmentNANA-2.7NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:StockIssuedDuringPeriodValueNewIssues █▁34.9519.699NANANA3.41NA36.07430.93138.6340.1830.017.993NANANANANANANANANA0.0047.3954.6359.8645.22912.5277.39954.574NANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▃▇▆▅▃█▆▁▂▅▄▃▄▅▄▂▃▅▅▃▂▆▅▃▃▆▅▃▄█▅▃▄▆▄▂▄▆▄▄▄▅▅▄▃87.19195.62286.607220.365182.11279.29339.177225.998-24.4791.584182.5140.79970.791105.791176.11132.40852.95486.539185.734173.82657.42345.226258.95208.46179.07294.661212.468192.77373.504137.037313.231195.03697.052136.874255.378154.62149.748124.993215.033157.32133.834120.461180.113168.149118.25585.116
us-gaap:NetCashProvidedByUsedInInvestingActivities ▄▅▄▄▅▃▄▄▄▄▁▄▄▅▄▅▅▇▅▅▅▅█▄▃▄▃▅▃▁▄▃▃▄▃▃▃▄▄▅▄▅▆▅▃▄-160.173-106.327-168.409-165.296-94.068-202.47-155.236-143.567-144.949-160.109-349.577-139.079-122.007-100.244-115.22-76.421-68.11645.589-50.779-76.774-98.007-79.535161.563-141.638-242.165-160.213-260.693-57.777-205.408-380.313-177.295-194.827-239.726-170.813-235.595-238.767-257.148-156.442-138.743-106.901-136.748-82.15321.223-98.284-208.596-122.287
us-gaap:NetCashProvidedByUsedInFinancingActivities ▆▅▄▅▄▇▃▄▇▇▇▅▆▅▅▅▅▄▄▄▆▆▁▄▇▆▄▅▇█▄▅▇▆▅▆▇▅▅▅▅▄▅▄▆▅75.8346.254-124.721-53.357-140.212173.247-184.482-87.397191.673154.298153.94823.69834.11218.618-63.647-58.6794.476-127.5-148.717-122.30135.44940.655-424.519-122.496185.258106.027-103.4948.5138.48281.708-156.812-48.995183.65259.021-44.97656.744217.837-39.977-32.205-39.153-25.422-124.411-15.53-99.55749.482-31.162
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:DeferredIncomeTaxExpenseBenefit ▄▄▄▅▄▄▅▅▄▅▅▅▄▄▄▄▄▄▄▄▄▄▄▄█▁▅▄▅▅▅▅▄▅▃▄▅▅▅▅▅▅▄▅▅▄4.6559.843-18.2113.5281.0681.81314.19326.46910.09512.65817.30738.2426.254-2.068-8.646-11.484-4.961-0.332-0.703-4.954-3.2946.902-12.335-12.238185.507-160.63350.009-23.13524.17635.96540.56626.422-24.87344.663-47.813-36.67744.39132.59638.9419.02526.45834.502-4.73735.56427.5328.226
us-gaap:DepreciationDepletionAndAmortization ▄▄▄▄▄▃▃▃▃▂▂▁▁▁▁▁▁▁▁▁▁▂▃▂▁▇▇██▇▇█▇▇▇▆▅▆▆▆▅▅▅▅▅▅73.66173.72372.26872.08471.50869.23968.0865.02163.01959.89758.90755.01653.55352.72952.34852.15551.65851.32553.09254.09454.24860.25962.76157.81754.15495.50795.188103.497103.12699.55798.0499.96695.28993.56198.34791.8583.62785.3886.53488.89783.2984.67483.77784.84181.54778.678
us-gaap:IncreaseDecreaseInAccountsPayable ▅▂▃▄▅▂▄▄▄▃▄▃▆▂▃▄▅▂▃▄▆▂▃▄█▁▂▄▃▃▃▄▆▂▃▅▅▂▃▃▄▂▃▅▄▂38.12-41.965-3.175.73837.492-24.10517.01711.6641.0420.3564.9540.40747.612-31.864-4.08418.48634.991-23.38-8.4758.17544.544-37.205-12.85117.04198.261-53.334-23.0581.27-11.752-11.525-10.7336.87754.031-35.091-15.45928.9322.732-29.851-4.226-4.8418.678-21.875-1.94932.94621.631-34.795
us-gaap:IncreaseDecreaseInInventories ▅▇▅▄▅▇▄▂▆▆▅▄▆▇▄▄▅▆▄▃▅▆▅▁▆█▅▃▇▆▃▃▆▆▅▄▆██▅▄▄▅▅▄▄-0.28325.613-2.36-16.695-3.06129.337-6.851-38.78214.89521.4078.011-8.61117.39929.997-7.088-15.62-0.10313.676-6.586-19.0360.89122.2983.181-53.68523.19644.408-1.415-28.70429.04819.809-28.89-31.48510.79719.1261.948-17.98120.0138.35745.238.15-15.52-13.6347.837-0.123-6.244-6.198
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▃▇▆▅▃█▆▁▂▅▄▃▄▅▄▂▃▅▅▃▂▆▅▃▃▆▅▃▄█▅▃▄▆▄▂▄▆▄▄▄▅▅▄▃87.19195.62286.607220.365182.11279.29339.177225.998-24.4791.584182.5140.79970.791105.791176.11132.40852.95486.539185.734173.82657.42345.226258.95208.46179.07294.661212.468192.77373.504137.037313.231195.03697.052136.874255.378154.62149.748124.993215.033157.32133.834120.461180.113168.149118.25585.116
us-gaap:NetIncomeLoss ▇▆▇█▇▆▇█▇▆▇▇▆▆▇▇▆▆▇▇▄▆▆▄▂▁▇▇▆▇▇▇▆▇▅▅▆▆▇▇▆▆▇▇▆▆100.1952.131112.294153.07899.70325.1395.065137.63761.82540.92678.828107.25143.80242.437115.31287.35141.21537.32565.73182.986-109.15324.86952.534-139.448-229.604-305.91784.256103.20954.10656.66291.4584.45646.51256.515-60.986-29.67154.11335.7961.00863.97445.06742.97788.93961.0148.93841.772
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInInvestingActivities ▄▅▄▄▅▃▄▄▄▄▁▄▄▅▄▅▅▇▅▅▅▅█▄▃▄▃▅▃▁▄▃▃▄▃▃▃▄▄▅▄▅▆▅▃▄-160.173-106.327-168.409-165.296-94.068-202.47-155.236-143.567-144.949-160.109-349.577-139.079-122.007-100.244-115.22-76.421-68.11645.589-50.779-76.774-98.007-79.535161.563-141.638-242.165-160.213-260.693-57.777-205.408-380.313-177.295-194.827-239.726-170.813-235.595-238.767-257.148-156.442-138.743-106.901-136.748-82.15321.223-98.284-208.596-122.287
us-gaap:PaymentsToAcquireProductiveAssets ▃▂▃▄▂▃▃▃▃▃▅▃▂▂▂▁▁▁▁▁▂▂▃▃▄▄█▆▅▄▆▅▆▄▆▆▅▄▃▂▃▁150.846111.091144.165165.042109.315139.485153.029141.362147.835133.839222.631134.987105.476105.136119.29878.3271.44872.31684.3183.775104.904115.194140.892128.585166.435189.463333.371248.605210.48179.646260.935217.026242.964188.475243.144241.327214.02174.429157.539114.527142.2782.664NANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInFinancingActivities ▆▅▄▅▄▇▃▄▇▇▇▅▆▅▅▅▅▄▄▄▆▆▁▄▇▆▄▅▇█▄▅▇▆▅▆▇▅▅▅▅▄▅▄▆▅75.8346.254-124.721-53.357-140.212173.247-184.482-87.397191.673154.298153.94823.69834.11218.618-63.647-58.6794.476-127.5-148.717-122.30135.44940.655-424.519-122.496185.258106.027-103.4948.5138.48281.708-156.812-48.995183.65259.021-44.97656.744217.837-39.977-32.205-39.153-25.422-124.411-15.53-99.55749.482-31.162
us-gaap:ProceedsFromIssuanceOfLongTermDebt ▄▄▃▁▂▇▇▂▆▅▆▄▅▄▃▄▃▄▂▂▅▆▃▃▅▅▂▆▅█▃▃█▄▄▄▇▃▃▃78.47493.29516.848-100.275-47.621248.021296.731-66.251227.637141.338209.877116.206139.158101.5887.37569.613.84259.985-32.713-45.848161.04226.58518.456.482171.656149.332-66.267230.904131.946309.50110.60646.857338.446112.01567.514100.498299.9450.00.0-5.7NANA2.401-65.193NANA
us-gaap:RepaymentsOfLongTermDebt ▃▄▄▂▄▃▇▄▃▄▃▄▄▃▃▄▂▅▄▃▃▅█▄▃▄▄▅▄▄▅▃▅▄▄▃▄▃▅▃▁▄▃▃▃▃-5.1553.30174.935-88.526125.98336.242301.96166.99546.99752.96417.20553.79466.47437.04733.42690.693-54.002147.27779.21439.66231.916164.855423.165108.196-16.02554.16249.812207.45253.30758.232167.72741.507147.3567.12365.31614.85450.3088.297168.956-2.603-161.83280.6321.213-6.731-1.2930.479
us-gaap:PaymentsOfDividends ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▃▅▄▄▄█▂▁▄█▂▁▄42.7442.61141.60941.60841.60841.5840.46140.22539.87539.69538.71438.71438.57238.57337.59637.59637.76837.76736.7936.79136.79136.78435.80735.73435.68735.60734.60734.38833.9833.73732.74532.74532.7440.17164.37431.831.831.794215.796-30.85-92.39630.773208.504-29.802-89.29429.749
us-gaap:PaymentsForRepurchaseOfCommonStock ▁█0.06.701NANANANA0.00.00.00.00.00.00.05.020.00.00.01.6840.00.00.00.0NANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value202201201201201201200200199198196196196195195195195195195195195195195195195195194194194191189189189189189189189189189189189189188188188188188
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.42.52.52.52.52.62.62.62.62.72.82.93.03.13.13.13.13.23.13.13.13.03.02.82.72.72.52.52.52.62.72.62.72.82.82.72.72.92.93.03.03.13.03.03.13.23.1

us-gaap:CommonStockValue us-gaap:ConsolidatedEntities

srt:ParentCompany


Common
Period End2020-12-312019-12-312018-12-312017-12-31
Value201200196195
Percentage of CommonStockValue100.0100.0100.0100.0
Percentage of Assets2.52.62.83.1
Percentage of Assets srt:ParentCompany6.26.74.74.9

Preferred Stock Par Or Stated Value Per Share

us-gaap:PreferredStockParOrStatedValuePerShare us-gaap:StatementClassOfStock

us-gaap:PreferredStockParOrStatedValuePerShare

us-gaap:PreferredStock


Preferred
Period End2020-12-31
Value100.0
Percentage of PreferredStockParOrStatedValuePerShare100.0

Common Stock Shares Issued

us-gaap:CommonStockSharesIssued

us-gaap:CommonStockSharesIssued


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value202201201201201201200200199198196196196195195195195195195195195195195195195195194194194191189189189189189189189189189189189189188188188188188
Percentage of CommonStockSharesIssued100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CommonStockSharesIssued us-gaap:ConsolidatedEntities

srt:ParentCompany


Common
Period End2020-12-312019-12-312018-12-312017-12-31
Value201200196195
Percentage of CommonStockSharesIssued100.0100.0100.0100.0

us-gaap:CommonStockSharesIssued us-gaap:StatementClassOfStock

mdu:Atthemarketoffering


Common
Period End2021-03-312019-12-31
Value0.672263.6
Percentage of CommonStockSharesIssued0.31.8

us-gaap:CommonStockSharesIssued us-gaap:StatementEquityComponents

us-gaap:CommonStock


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value202201201201201201200200199198196196196195195195195195195195194189189189188188184
Percentage of CommonStockSharesIssued100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

Common Stock Shares Authorized

us-gaap:CommonStockSharesAuthorized us-gaap:StatementClassOfStock

us-gaap:CommonStockSharesAuthorized

mdu:Atthemarketoffering


Common
Period End2021-06-302021-03-312020-12-312019-12-31
Value6.46.46.410.0
Percentage of CommonStockSharesAuthorized100.0100.0100.0100.0

Preferred Stock Shares Authorized

us-gaap:PreferredStockSharesAuthorized us-gaap:StatementClassOfStock

us-gaap:PreferredStockSharesAuthorized

us-gaap:PreferredStock


Preferred
Period End2020-12-31
Value2000000.0
Percentage of PreferredStockSharesAuthorized100.0

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2012002002002002002001991981961961961961951951951951961951951951951951951941941941941921901891891891891881881891891880.1887970.1889680.1888151880.1883380.1882670.18822
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2012002002002002002001991981961961961951951951951951951951951951951951951941941941931921891881881881881881881881881880.1887940.1887940.1886711880.188170.1881290.187963
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount


Antidilutive
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-06-30
Value87000.0187000.068000.0155000.0064000.0114000.0000000000087000.0000000434000.0000000
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount100.0100.0100.0100.00.0100.0100.00.00.00.00.00.00.00.00.00.00.0100.00.00.00.00.00.00.0100.00.00.00.00.00.00.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.50.260.560.760.50.130.470.690.310.210.40.550.220.220.590.450.210.190.340.42-0.560.130.27-0.72-1.18-1.570.430.530.280.30.480.450.250.3-0.32-0.160.290.190.320.340.240.23
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.50.260.560.760.50.130.470.690.310.210.40.550.220.220.590.450.210.190.330.42-0.560.130.27-0.72-1.18-1.570.430.530.280.30.480.440.240.3-0.32-0.160.290.190.320.340.240.23
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Income Loss From Continuing Operations Per Basic Share

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.50.260.560.760.50.130.470.680.320.210.390.550.220.220.590.460.220.180.340.450.240.130.240.320.11-1.570.420.530.280.30.480.450.250.3-0.37-0.160.260.190.390.340.240.220.490.320.260.22
Percentage of IncomeLossFromContinuingOperationsPerBasicShare100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Income Loss From Continuing Operations Per Diluted Share

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.50.260.560.760.50.130.470.680.320.210.390.550.220.220.590.460.220.180.330.450.240.130.240.320.11-1.570.420.530.280.30.480.440.240.3-0.37-0.160.260.190.390.340.240.220.490.320.260.22
Percentage of IncomeLossFromContinuingOperationsPerDilutedShare100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax


Comprehensive
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value10052104153100258913862418410744421138741366783-108.7772355-139.046-228.926-304.738791035457110844648-63.26-46.544772914956521576147
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.14.37.59.77.42.26.58.84.83.87.08.44.24.49.76.93.93.96.76.9-10.42.65.2-10.9-23.2-33.26.87.55.05.59.36.64.45.2-5.9-4.08.03.51.48.37.12.35.55.55.3

Income Loss From Continuing Operations

us-gaap:IncomeLossFromContinuingOperations

us-gaap:IncomeLossFromContinuingOperations


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value10052112153992594136634175107444111589443566884614325314-309.44580102525691844656-69.686-29.53249357464454292614841
Percentage of IncomeLossFromContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.04.28.19.67.32.16.98.74.83.86.38.44.14.39.97.04.23.86.57.34.41.63.04.21.4-33.76.97.54.85.47.76.64.46.1-6.4-2.55.14.27.05.64.94.78.95.45.45.0

us-gaap:IncomeLossFromContinuingOperations us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1756576.9851951487.5997.5975939137.52151
Percentage of IncomeLossFromContinuingOperations17.7107.750.94.619.9200.251.05.612.0143.651.912.617.1121.9
Percentage of Revenues1.24.64.10.41.54.33.50.50.65.43.31.10.75.2
Percentage of Revenues us-gaap:RegulatedOperation6.812.70.03.38.212.20.03.63.213.40.06.73.312.1

us-gaap:UnregulatedOperation


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value82-4.0055514679-25.594612855-17.92369336-9.206
Percentage of IncomeLossFromContinuingOperations82.3-7.749.195.480.1-100.249.094.488.0-43.648.187.482.9-21.9
Percentage of Revenues5.8-0.34.09.25.9-2.13.48.24.3-1.63.07.33.4-0.9
Percentage of Revenues us-gaap:UnregulatedOperation7.1-0.50.010.67.1-3.30.09.55.2-2.80.08.74.4-1.7

us-gaap:IncomeLossFromContinuingOperations us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:RegulatedOperation, mdu:Electric


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value10101516121115167.471159.5159.13313
Percentage of IncomeLossFromContinuingOperations10.320.613.611.012.244.516.312.011.837.712.514.220.731.2
Percentage of Revenues0.70.91.11.10.90.91.11.00.61.40.81.20.91.3
Percentage of Revenues us-gaap:RegulatedOperation mdu:Electric12.312.70.019.215.913.20.018.19.216.80.017.811.615.0

us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.7073630-17.614-0.9593224-15.625-6.2523623-11.887-6.85232
Percentage of IncomeLossFromContinuingOperations-0.769.427.0-11.5-1.0126.726.3-11.5-9.988.831.4-11.1-15.577.7
Percentage of Revenues-0.02.92.2-1.1-0.12.71.8-1.0-0.53.32.0-0.9-0.63.3
Percentage of Revenues us-gaap:RegulatedOperation mdu:NaturalGasDistribution-0.510.30.0-18.6-0.79.90.0-16.7-4.710.70.0-12.9-5.39.8

us-gaap:RegulatedOperation, mdu:Pipeline


Income
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value8.0899.1947.8128.6847.3866.933
Percentage of IncomeLossFromContinuingOperations8.117.65.18.728.95.1
Percentage of Revenues0.60.70.50.60.60.4
Percentage of Revenues us-gaap:RegulatedOperation mdu:Pipeline35.0122.627.937.1116.726.7

us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value51-30.8132510753-38.2152310229-34.449127824-23.521
Percentage of IncomeLossFromContinuingOperations51.3-59.122.570.153.1-149.624.375.446.2-83.817.173.555.2-56.1
Percentage of Revenues3.6-2.51.86.83.9-3.21.76.62.2-3.21.16.22.3-2.4
Percentage of Revenues us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting8.1-11.60.013.08.5-14.60.011.84.9-15.20.010.64.8-11.0

us-gaap:UnregulatedOperation, mdu:ConstructionServices


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value28293529271629212220259.2781415
Percentage of IncomeLossFromContinuingOperations28.857.231.419.528.065.930.615.536.248.734.08.632.036.0
Percentage of Revenues2.02.42.51.92.01.42.11.41.81.82.10.71.31.5
Percentage of Revenues us-gaap:UnregulatedOperation mdu:ConstructionServices5.55.80.05.45.63.30.04.44.94.80.02.84.44.5

us-gaap:UnregulatedOperation, mdu:Pipeline


Income
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value1.106-0.2960.1890.268-0.0130.801
Percentage of IncomeLossFromContinuingOperations1.1-0.60.10.3-0.10.6
Percentage of Revenues0.1-0.00.00.0-0.00.1
Percentage of Revenues us-gaap:UnregulatedOperation mdu:Pipeline23.8-12.34.66.3-0.312.2

us-gaap:UnregulatedOperation, us-gaap:CorporateAndOther


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.098-2.721-6.4848.745-1.256-4.185-5.5524.0042.795-3.332-2.6894.861-2.337-0.596
Percentage of IncomeLossFromContinuingOperations1.1-5.2-5.85.7-1.3-16.4-5.92.94.4-8.1-3.54.5-5.3-1.4
Percentage of Revenues0.1-0.2-0.50.6-0.1-0.3-0.40.30.2-0.3-0.20.4-0.2-0.1
Percentage of Revenues us-gaap:UnregulatedOperation us-gaap:CorporateAndOther3921.4-16005.90.036437.51121.4-23250.00.018200.011645.8-17536.80.010342.6-2596.7-1027.6

Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value123651351841233110916773489012154491061365947921266719459023-495.1729015679841281317184-125.349-49.78575531101016558
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues8.75.39.811.69.12.67.910.75.64.47.59.55.15.19.110.75.65.19.110.46.52.14.37.12.4-53.97.811.47.38.110.910.26.79.1-11.6-4.27.86.310.48.87.06.5

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value23122331235.9731431107.3171414107.551-9.3654615122537214.55813369.801-185.7271054272737462427-55.662-20.25326183637191541312425
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.61.11.72.01.70.51.12.00.80.71.21.11.00.8-0.83.71.41.32.53.12.00.51.22.91.0-20.20.94.02.52.73.13.62.43.0-5.1-1.72.82.13.43.32.11.84.02.82.73.0

us-gaap:IncomeTaxExpenseBenefit us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:InterestRateContract, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-0.036-0.037-0.036-0.037-0.036-0.036-0.037-0.036-0.0360.249-0.265-0.055-0.053-0.056-0.056-0.056-0.056-0.056-0.056-0.056-0.056-0.057-0.052-0.06-0.06-0.06
Percentage of IncomeTaxExpenseBenefit-0.2-0.3-0.2-0.1-0.2-0.6-0.3-0.1-0.33.4-1.8-0.4-0.5-0.70.6-0.1-0.4-0.5-0.2-0.1-0.3-1.3-0.4-0.2-0.60.0
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:InterestRateContract us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:IncomeTaxExpenseBenefit us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-0.16-0.151-0.174-0.152-0.155-0.149-0.192-0.095-0.089-0.1-0.279-0.142-0.145-0.155-0.036-0.203-0.19-0.217-2.101-0.143-0.150.969-0.247-0.233-0.42-0.23
Percentage of IncomeTaxExpenseBenefit-0.7-1.2-0.7-0.5-0.7-2.5-1.3-0.3-0.9-1.4-1.9-1.0-1.4-2.10.4-0.4-1.2-1.8-8.2-0.4-0.721.3-1.9-0.6-4.30.1
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.2-0.0-0.00.1-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-0.006-0.009-0.005-0.007-0.0020.00.00.001-0.003-0.007-0.009-0.009-0.01-0.007-0.015-0.014-0.017-0.019-0.02-0.018-0.019-0.019-0.017-0.015-0.015-0.019
Percentage of IncomeTaxExpenseBenefit-0.0-0.1-0.0-0.0-0.00.00.00.0-0.0-0.1-0.1-0.1-0.1-0.10.2-0.0-0.1-0.2-0.1-0.0-0.1-0.4-0.1-0.0-0.20.0
Percentage of Revenues-0.0-0.0-0.0-0.0-0.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Income Taxes Paid Net

us-gaap:IncomeTaxesPaidNet

us-gaap:IncomeTaxesPaidNet


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value321322420.736-0.001-10.291-2.3084.0950.0297.1544.8535.09-1.056651435-2.762324331-1.42912174.456-1.339244.182309.435-5.405324.597-7.2460.0670.7922.1330.285-0.956-24.2182.9069.9819.930.951
Percentage of IncomeTaxesPaidNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues2.31.11.62.70.1-0.0-0.7-0.10.30.00.60.40.5-0.15.61.13.3-0.33.23.63.0-0.21.21.40.5-0.12.10.32.80.9-0.52.60.4-0.80.00.10.20.0-0.1-2.10.31.11.00.1

us-gaap:IncomeTaxesPaidNet us-gaap:StatementOperatingActivitiesSegment

mdu:Continuinganddiscontinuedoperations


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value15420.7360.146-11.40.01.8680.1320.42.01.41.78.35.03.6-7.21.4440.3560.9-1.4
Percentage of IncomeTaxesPaidNet72.099.8100.0-14600.0110.8-0.045.6455.25.641.227.5-161.012.635.610.2260.74.50.82.998.0
Percentage of Revenues1.12.70.10.0-0.80.00.10.00.00.20.10.20.70.40.3-0.80.10.00.1-0.2
Percentage of Revenues mdu:Continuinganddiscontinuedoperations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value23232323242424252523222020202020202020222223232223232222212020212120191917191919202221202020
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.61.91.71.51.82.11.81.62.02.11.91.62.02.11.81.61.92.22.01.82.12.62.21.82.42.51.91.62.02.01.71.62.02.21.81.71.82.31.81.72.22.42.01.92.32.5

us-gaap:InterestExpense us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:InterestRateContract, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value0.1480.1480.1480.1480.1480.1470.1480.1480.1470.1480.1480.1470.1480.1480.1470.1480.1480.1470.1480.1480.1470.1490.1570.160.160.159
Percentage of InterestExpense0.60.60.60.60.60.60.60.60.60.60.70.70.70.70.70.70.70.70.70.70.70.60.70.70.70.7
Percentage of Revenues0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:InterestRateContract us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Interest Paid Net

us-gaap:InterestPaidNet

us-gaap:InterestPaidNet


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3114251531152818261924182117211821172121212320252123192218202118192116221322142315251526
Percentage of InterestPaidNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues2.21.21.81.02.31.32.11.22.01.72.01.52.01.81.81.52.01.92.11.82.02.61.92.02.22.61.71.61.72.01.81.51.82.31.51.91.42.61.42.01.62.81.52.3

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1005211215399259513761407810743421158741376582-109.1532452-139.448-229.604-305.91784103545691844656-60.986-29.67154356163454288614841
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.04.28.19.67.32.16.98.84.73.86.58.44.14.39.96.93.94.06.56.9-10.52.74.9-10.9-23.3-33.37.27.54.95.47.76.64.46.1-5.6-2.55.64.25.75.64.84.88.55.45.45.0

us-gaap:NetIncomeLoss us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:InterestRateContract, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.112-0.111-0.112-0.111-0.112-0.111-0.111-0.112-0.111-0.3970.117-0.092-0.095-0.092
Percentage of NetIncomeLoss-0.1-0.2-0.1-0.1-0.1-0.4-0.1-0.1-0.2-1.00.1-0.1-0.2-0.2
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:InterestRateContract us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount

srt:RestatementAdjustment


Net
Period End2020-12-312020-03-31
Value4.4-6.7
Percentage of NetIncomeLoss3.9-26.7
Percentage of Revenues0.3-0.6
Percentage of Revenues srt:RestatementAdjustment0.087.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.594-0.612-0.639-0.61-0.599-0.572-0.723-0.4-0.399-0.735-0.781-0.567-0.827-0.54
Percentage of NetIncomeLoss-0.6-1.2-0.6-0.4-0.6-2.3-0.8-0.3-0.6-1.8-1.0-0.5-1.9-1.3
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.0-0.0-0.1-0.1-0.0-0.1-0.1
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.457-0.466-0.509-0.471-0.48-0.462-0.608-0.292-0.276-0.31-0.864-0.442-0.449-0.418
Percentage of NetIncomeLoss-0.5-0.9-0.5-0.3-0.5-1.8-0.6-0.2-0.4-0.8-1.1-0.4-1.0-1.0
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.025-0.035-0.018-0.028-0.0070.001-0.0040.004-0.012-0.028-0.034-0.033-0.034-0.03
Percentage of NetIncomeLoss-0.0-0.1-0.0-0.0-0.00.0-0.00.0-0.0-0.1-0.0-0.0-0.1-0.1
Percentage of Revenues-0.0-0.0-0.0-0.0-0.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-03-31
Value1005215399251376140107434237
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.04.29.67.32.18.84.73.88.44.14.34.0
Percentage of Revenues us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.0

Operating Expenses

us-gaap:OperatingExpenses

us-gaap:OperatingExpenses


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value12851142123913831224114012471374120610261091114099090610391116987870904106195486310071170940139210531193995939103711359698271190120787678193910328488239121016817751
Percentage of OperatingExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues90.393.189.587.289.995.290.687.992.594.190.289.193.092.989.287.792.592.889.087.991.595.494.891.495.4151.690.687.191.090.187.688.391.488.8110.1102.990.591.788.189.691.291.387.590.390.290.1

Operating Income Loss

us-gaap:OperatingIncomeLoss

us-gaap:OperatingIncomeLoss


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value137851452031385713018997641181407369125156796711114688415510945-474.3471091769810214714991104-109.529-34.035917112611982781301088882
Percentage of OperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues9.76.910.512.810.14.89.412.17.55.99.810.97.07.110.812.37.57.211.012.18.54.65.28.64.6-51.69.412.99.09.912.411.78.611.2-10.1-2.99.58.311.910.48.88.712.59.79.89.9

us-gaap:OperatingIncomeLoss us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value72-34.8893414874-43.2693214346-41.582010937-26.309
Percentage of OperatingIncomeLoss52.6-41.023.772.954.1-75.824.875.547.5-64.717.678.350.4-37.9
Percentage of Revenues5.1-2.82.59.45.5-3.62.39.13.5-3.81.78.63.5-2.7
Percentage of Revenues mdu:ConstructionMaterialsAndContracting11.4-13.10.018.112.0-16.50.016.57.8-18.30.014.77.3-12.3

mdu:ConstructionServices


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3740454037233729312734111920
Percentage of OperatingIncomeLoss27.447.331.219.927.441.728.415.832.842.829.58.526.229.7
Percentage of Revenues2.73.33.32.62.82.02.71.92.52.52.90.91.82.1
Percentage of Revenues mdu:ConstructionServices7.27.80.07.47.64.60.06.36.96.50.03.66.06.2

mdu:Electric


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value12131421121414219.7911712211318
Percentage of OperatingIncomeLoss9.316.310.010.49.326.011.011.610.128.010.815.117.626.2
Percentage of Revenues0.91.11.11.30.91.21.01.40.81.61.11.71.21.9
Percentage of Revenues mdu:Electric15.316.40.024.216.817.30.024.412.119.40.024.616.620.8

mdu:NaturalGasDistribution


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3.6015340-18.3930.6784937-15.565-2.6215039-11.665-4.37148
Percentage of OperatingIncomeLoss2.662.928.0-9.00.587.628.5-8.2-2.778.433.7-8.3-5.970.0
Percentage of Revenues0.34.42.9-1.20.04.22.7-1.0-0.24.63.3-0.9-0.45.0
Percentage of Revenues mdu:NaturalGasDistribution2.315.30.0-19.40.515.30.0-16.6-2.014.70.0-12.6-3.414.6

mdu:Pipeline


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value111211121111
Percentage of OperatingIncomeLoss8.014.75.88.820.06.0
Percentage of Revenues0.81.00.70.91.00.7
Percentage of Revenues mdu:Pipeline39.9126.536.744.2107.235.1

us-gaap:CorporateAndOther


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.02-0.198-3.5080.154-0.0820.267-1.324-1.2851.2990.125-0.4960.0320.1970.189
Percentage of OperatingIncomeLoss-0.0-0.2-2.40.1-0.10.5-1.0-0.71.30.2-0.40.00.30.3
Percentage of Revenues-0.0-0.0-0.30.0-0.00.0-0.1-0.10.10.0-0.00.00.00.0
Percentage of Revenues us-gaap:CorporateAndOther-71.4-1164.70.0641.773.21483.30.0-5840.95412.5657.90.068.1218.9325.9

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value0.5420.568-7.8290.560.5860.707-5.4240.4120.4780.7745.2770.5160.7250.433-1.9930.4480.396-0.4522.1580.3150.376-1.4342.6960.4020.6781.179-5.0710.1660.340.66718-0.116-0.206-7.894-2.273-16.87323-5.929-46.4133120
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues0.00.0-0.60.00.00.1-0.40.00.00.10.40.00.10.0-0.20.00.0-0.00.20.00.0-0.20.30.00.10.1-0.40.00.00.11.6-0.0-0.0-0.8-0.2-1.42.4-0.7-4.42.72.2

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.4570.4660.4710.480.4620.2920.2760.315.3050.4420.4490.418-2.0270.3330.312-0.562.1470.2360.248-1.5952.620.3820.5840.375-5.1920.2610.2450.275190.2720.4240.648
Percentage of OtherComprehensiveIncomeLossNetOfTax84.382.084.181.965.370.957.740.1100.585.761.996.5101.774.378.8123.999.574.966.0111.297.295.086.131.8102.4157.272.141.2102.5-234.5-205.8-8.2
Percentage of Revenues0.00.00.00.00.00.00.00.00.40.00.00.0-0.20.00.0-0.10.20.00.0-0.20.20.00.10.0-0.40.00.00.01.60.00.00.1
Percentage of Revenues us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.1120.1110.1110.1120.1110.1120.1110.397-0.1170.0920.0950.0920.0910.0920.0920.0910.0920.0920.0910.0920.1050.10.10.0990.2550.0820.0130.344-0.511-0.51-0.141-8.621
Percentage of OtherComprehensiveIncomeLossNetOfTax20.719.519.819.115.727.223.251.3-2.217.813.121.2-4.620.523.2-20.14.329.224.2-6.43.924.914.78.4-5.049.43.851.6-2.7439.768.4109.2
Percentage of Revenues0.00.00.00.00.00.00.00.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.9
Percentage of Revenues us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value-0.027-0.009-0.022-0.0060.1340.0080.0910.0670.089-0.018-0.009-0.075-0.0420.0080.0070.008-0.08-0.0090.0060.044-0.032-0.007-0.0150.015-0.03-0.0310.040.002-0.0050.028-0.099-0.009
Percentage of OtherComprehensiveIncomeLossNetOfTax-5.0-1.6-3.9-1.019.01.919.08.71.7-3.5-1.2-17.32.11.81.8-1.8-3.7-2.91.6-3.1-1.2-1.7-2.21.30.6-18.711.80.3-0.0-24.148.10.1
Percentage of Revenues-0.0-0.0-0.0-0.00.00.00.00.00.0-0.0-0.0-0.0-0.00.00.00.0-0.0-0.00.00.0-0.0-0.0-0.00.0-0.0-0.00.00.0-0.00.0-0.0-0.0
Percentage of Revenues us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value0.5420.5680.560.5860.7070.4120.4780.7745.2770.5160.7250.433-1.9930.4480.396-0.4522.1580.3150.376-1.4342.6960.4020.6781.179-5.0710.166
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues0.00.00.00.00.10.00.00.10.40.00.10.0-0.20.00.0-0.00.20.00.0-0.20.30.00.10.1-0.40.0
Percentage of Revenues us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Other Income

us-gaap:OtherIncome us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount

us-gaap:OtherIncome

srt:RestatementAdjustment


Other
Period End2020-12-31
Value6500000.0
Percentage of OtherIncome100.0
Percentage of Revenues0.5
Percentage of Revenues srt:RestatementAdjustment0.0

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value9.0273.354134.61210-1.0053.593.0141.6157.595-5.1022.6831.5990.5821.2941.0110.7821.0171.2941.7410.8721.246123.4982.322.3242.412.6442.7772.1321.7652.3261.4361.2422.5921.7021.2491.0981.431.2821.9081.91.0891.742.6862.502
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues0.60.30.90.30.7-0.10.30.20.10.7-0.40.20.20.10.10.10.10.10.10.10.10.11.20.30.20.30.20.20.30.20.10.20.10.10.20.10.10.10.10.10.20.20.10.20.30.3

us-gaap:OtherNonoperatingIncomeExpense us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value-0.617-0.617-0.683-0.623-0.635-0.611-0.8-0.387-0.365-0.41-1.143-0.584-0.594-0.573-0.047-0.536-0.502-0.574
Percentage of OtherNonoperatingIncomeExpense-6.8-18.4-5.2-13.5-6.360.8-22.3-12.8-22.6-5.422.4-21.8-37.1-98.5-3.6-53.0-64.2-56.4
Percentage of Revenues-0.0-0.1-0.0-0.0-0.0-0.1-0.1-0.0-0.0-0.0-0.1-0.0-0.1-0.1-0.0-0.0-0.0-0.1
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-0.031-0.044-0.023-0.035-0.0090.001-0.0040.005-0.015-0.035-0.043-0.042-0.044-0.037-0.042-0.041-0.048-0.054-0.057-0.051-0.055-0.055-0.05-0.043-0.043-0.055
Percentage of OtherNonoperatingIncomeExpense-0.3-1.3-0.2-0.8-0.1-0.1-0.10.2-0.9-0.50.8-1.6-2.8-6.4-3.2-4.1-6.1-5.3-4.4-2.9-6.3-4.4-0.4-1.2-1.9-2.4
Percentage of Revenues-0.0-0.0-0.0-0.0-0.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Revenues

us-gaap:Revenues

us-gaap:Revenues


Revenues
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1423122713851587136211971378156313031091120912801064976116512721067937101612081043905106212809869181163137010941042118412851060931108111739678521065115293090110421125906834
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value-12.44-30.935-26.12-7.543-12.222-31.085-25.821-8.043-11.281-32.003-22.646-7.171-9.981-24.509-5.586
Percentage of Revenues-0.9-2.5-1.9-0.5-0.9-2.6-1.9-0.5-0.9-2.9-1.9-0.6-0.9-2.5-0.4
Percentage of Revenues-0.9-2.5-1.9-0.5-0.9-2.6-1.9-0.5-0.9-2.9-1.9-0.6-0.9-2.5-0.4
Percentage of Revenues us-gaap:IntersegmentElimination100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:IntersegmentElimination, us-gaap:RegulatedOperation


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value7.97326213.9238.23825203.757.42623193.076.446213.081
Percentage of Revenues0.62.11.50.20.62.11.50.20.62.21.60.20.62.20.2
Percentage of Revenues0.62.11.50.20.62.11.50.20.62.21.60.20.62.20.2
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:RegulatedOperation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:UnregulatedOperation


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value4.4674.6674.8423.623.9845.5224.8824.2933.8558.0813.3184.1013.5352.7742.505
Percentage of Revenues0.30.40.30.20.30.50.40.30.30.70.30.30.30.30.2
Percentage of Revenues0.30.40.30.20.30.50.40.30.30.70.30.30.30.30.2
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:UnregulatedOperation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:IntersegmentElimination, us-gaap:RegulatedOperation, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value0.1360.136-0.0950.1950.1960.1950.00.00.00.00.00.00.0
Percentage of Revenues0.00.0-0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.0-0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:RegulatedOperation mdu:Electric100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.0

us-gaap:IntersegmentElimination, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value0.1420.142-0.0210.1850.1850.1850.00.00.00.00.00.00.0
Percentage of Revenues0.00.0-0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.0-0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:RegulatedOperation mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.0

us-gaap:IntersegmentElimination, us-gaap:RegulatedOperation, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value7.695253.5437.857253.75
Percentage of Revenues0.52.10.20.62.10.2
Percentage of Revenues0.52.10.20.62.10.2
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:RegulatedOperation mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value0.1420.0620.1550.110.090.0630.6780.1240.1680.0950.1680.1650.2350.1010.142
Percentage of Revenues0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:UnregulatedOperation, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value0.7971.0421.3640.4250.7792.471.2941.2260.7210.1290.3490.7820.540.0110.415
Percentage of Revenues0.10.10.10.00.10.20.10.10.10.00.00.10.10.00.0
Percentage of Revenues0.10.10.10.00.10.20.10.10.10.00.00.10.10.00.0
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:UnregulatedOperation mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:UnregulatedOperation, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value0.1670.2390.0790.1420.0160.081
Percentage of Revenues0.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:UnregulatedOperation mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:UnregulatedOperation, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-30
Value3.3613.3243.0063.0062.9732.9732.8952.8622.8797.8242.7093.0372.6672.6381.91
Percentage of Revenues0.20.30.20.20.20.20.20.20.20.70.20.20.30.30.2
Percentage of Revenues0.20.30.20.20.20.20.20.20.20.70.20.20.30.30.2
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:UnregulatedOperation us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:IntersegmentElimination, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.142-0.062-0.155-0.11-0.09-0.063-0.678-0.124-0.168-0.095-0.168-0.165-0.235-0.101
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:IntersegmentElimination mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.797-1.042-1.364-0.425-0.779-2.47-1.294-1.226-0.721-0.129-0.349-0.782-0.54-0.011
Percentage of Revenues-0.1-0.1-0.1-0.0-0.1-0.2-0.1-0.1-0.1-0.0-0.0-0.1-0.1-0.0
Percentage of Revenues-0.1-0.1-0.1-0.0-0.1-0.2-0.1-0.1-0.1-0.0-0.0-0.1-0.1-0.0
Percentage of Revenues us-gaap:IntersegmentElimination mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.136-0.1360.095-0.195-0.196-0.1950.00.00.00.00.00.00.00.0
Percentage of Revenues-0.0-0.00.0-0.0-0.0-0.00.00.00.00.00.00.00.00.0
Percentage of Revenues-0.0-0.00.0-0.0-0.0-0.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination mdu:Electric100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.00.0

us-gaap:IntersegmentElimination, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.142-0.1420.021-0.185-0.185-0.1850.00.00.00.00.00.00.00.0
Percentage of Revenues-0.0-0.00.0-0.0-0.0-0.00.00.00.00.00.00.00.00.0
Percentage of Revenues-0.0-0.00.0-0.0-0.0-0.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:IntersegmentElimination mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.00.0

us-gaap:IntersegmentElimination, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value-7.862-26.229-3.622-7.999-25.199-3.831
Percentage of Revenues-0.6-2.1-0.2-0.6-2.1-0.2
Percentage of Revenues-0.6-2.1-0.2-0.6-2.1-0.2
Percentage of Revenues us-gaap:IntersegmentElimination mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-3.361-3.324-3.006-3.006-2.973-2.973-2.895-2.862-2.879-7.824-2.709-3.037-2.667-2.638
Percentage of Revenues-0.2-0.3-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.7-0.2-0.2-0.3-0.3
Percentage of Revenues-0.2-0.3-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.7-0.2-0.2-0.3-0.3
Percentage of Revenues us-gaap:IntersegmentElimination us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:MajorCustomers

mdu:CommercialUtilitySales


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value81152125647014814065741571236473151
Percentage of Revenues5.712.59.14.15.212.410.24.25.714.410.25.06.915.5
Percentage of Revenues5.712.59.14.15.212.410.24.25.714.410.25.06.915.5
Percentage of Revenues mdu:CommercialUtilitySales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:IndustrialUtilitySales


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1618171213181813141715131316
Percentage of Revenues1.21.51.30.81.01.61.30.91.11.61.31.01.31.7
Percentage of Revenues1.21.51.30.81.01.61.30.91.11.61.31.01.31.7
Percentage of Revenues mdu:IndustrialUtilitySales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherUtilitySales


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.8251.5661.6161.7791.5911.6481.8681.8621.8791.7991.792.0561.8741.836
Percentage of Revenues0.10.10.10.10.10.10.10.10.10.20.10.20.20.2
Percentage of Revenues0.10.10.10.10.10.10.10.10.10.20.10.20.20.2
Percentage of Revenues mdu:OtherUtilitySales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ResidentialUtilitySales


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1122361918110621919875972371807595228
Percentage of Revenues7.919.313.95.17.818.314.44.87.521.714.95.99.023.4
Percentage of Revenues7.919.313.95.17.818.314.44.87.521.714.95.99.023.4
Percentage of Revenues mdu:ResidentialUtilitySales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments

mdu:CommercialUtilitySales, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3332323529333636333532363234
Percentage of Revenues2.42.72.32.22.22.82.62.32.53.32.72.83.13.6
Percentage of Revenues2.42.72.32.22.22.82.62.32.53.32.72.83.13.6
Percentage of Revenues mdu:CommercialUtilitySales mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:CommercialUtilitySales, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value471209328411141042941121902840116
Percentage of Revenues3.39.86.71.83.09.67.61.93.211.27.52.23.812.0
Percentage of Revenues3.39.86.71.83.09.67.61.93.211.27.52.23.812.0
Percentage of Revenues mdu:CommercialUtilitySales mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:IndustrialUtilitySales, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value10109.8778.4288.07210109.3489.3448.8848.6198.7388.2268.77
Percentage of Revenues0.70.80.70.50.60.90.70.60.70.80.70.70.80.9
Percentage of Revenues0.70.80.70.50.60.90.70.60.70.80.70.70.80.9
Percentage of Revenues mdu:IndustrialUtilitySales mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:IndustrialUtilitySales, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value6.188.8127.614.4545.6588.5218.44.3075.5778.6117.1464.4215.2277.809
Percentage of Revenues0.40.70.50.30.40.70.60.30.40.80.60.30.50.8
Percentage of Revenues0.40.70.50.30.40.70.60.30.40.80.60.30.50.8
Percentage of Revenues mdu:IndustrialUtilitySales mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherUtilitySales, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.8251.5661.6161.7791.5911.6481.8681.8621.8791.7991.792.0561.8741.836
Percentage of Revenues0.10.10.10.10.10.10.10.10.10.20.10.20.20.2
Percentage of Revenues0.10.10.10.10.10.10.10.10.10.20.10.20.20.2
Percentage of Revenues mdu:OtherUtilitySales mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ResidentialUtilitySales, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value2933293327323230263628312635
Percentage of Revenues2.12.72.12.12.12.72.31.92.03.42.32.52.53.6
Percentage of Revenues2.12.72.12.12.12.72.31.92.03.42.32.52.53.6
Percentage of Revenues mdu:ResidentialUtilitySales mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ResidentialUtilitySales, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value83203162487818616644712001524368192
Percentage of Revenues5.916.511.73.05.815.612.12.95.418.412.63.46.519.8
Percentage of Revenues5.916.511.73.05.815.612.12.95.418.412.63.46.519.8
Percentage of Revenues mdu:ResidentialUtilitySales mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ProductOrService

mdu:ConstructionMaterials


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value498216360608482207364638444179322538387173
Percentage of Revenues35.017.626.038.335.417.426.540.934.116.426.742.136.417.8
Percentage of Revenues35.017.626.038.335.417.426.540.934.116.426.742.136.417.8
Percentage of Revenues mdu:ConstructionMaterials100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ContractingServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value28096219448303982464612978323840924774
Percentage of Revenues19.77.815.828.322.38.217.929.522.87.619.731.923.37.6
Percentage of Revenues19.77.815.828.322.38.217.929.522.87.619.731.923.37.6
Percentage of Revenues mdu:ContractingServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:InsideSpecialtyContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value347355347352324372330317319299259217216233
Percentage of Revenues24.428.925.122.223.831.124.020.324.527.421.417.020.323.9
Percentage of Revenues24.428.925.122.223.831.124.020.324.527.421.417.020.323.9
Percentage of Revenues mdu:InsideSpecialtyContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasGathering


Revenuesus-gaap:
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.6210.9731.1812.092.1372.512.3962.1212.2592.322.312.27
Percentage of Revenues0.00.10.10.20.20.20.20.20.20.20.20.2
Percentage of Revenues0.00.10.10.20.20.20.20.20.20.20.20.2
Percentage of Revenues mdu:NaturalGasGathering100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasTransportation


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3941403838393836353635323132
Percentage of Revenues2.73.43.02.42.83.32.82.32.73.43.02.52.93.4
Percentage of Revenues2.73.43.02.42.83.32.82.32.73.43.02.52.93.4
Percentage of Revenues mdu:NaturalGasTransportation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value2018171617171720202321181918
Percentage of Revenues1.41.51.21.11.31.51.31.31.62.21.81.41.81.9
Percentage of Revenues1.41.51.21.11.31.51.31.31.62.21.81.41.81.9
Percentage of Revenues mdu:OtherRevenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OutsideSpecialtyContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1651511711871601301391511331071091009587
Percentage of Revenues11.612.312.411.811.810.910.29.710.29.89.07.98.98.9
Percentage of Revenues11.612.312.411.811.810.910.29.710.29.89.07.98.98.9
Percentage of Revenues mdu:OutsideSpecialtyContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1409121613641576134711831364154912871081118812651051964
Percentage of Revenues99.099.098.599.398.898.899.099.198.799.198.298.898.798.8
Percentage of Revenues99.099.098.599.398.898.899.099.198.799.198.298.898.798.8
Percentage of Revenues mdu:RevenueFromContractsWithCustomers100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenuesOutOfScope


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1411201115131314161021151311
Percentage of Revenues1.01.01.50.71.21.21.00.91.30.91.81.21.31.2
Percentage of Revenues1.01.01.50.71.21.21.00.91.30.91.81.21.31.2
Percentage of Revenues mdu:RevenuesOutOfScope100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NaturalGasStorage


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3.0944.0294.8833.8853.1043.0463.3953.0442.6232.6462.982.7952.6343.134
Percentage of Revenues0.20.30.40.20.20.30.20.20.20.20.20.20.20.3
Percentage of Revenues0.20.30.40.20.20.30.20.20.20.20.20.20.20.3
Percentage of Revenues us-gaap:NaturalGasStorage100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ProductOrService, us-gaap:StatementBusinessSegments

mdu:ConstructionMaterials, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value498216360608482207364638444179322538387173
Percentage of Revenues35.017.626.038.335.417.426.540.934.116.426.742.136.417.8
Percentage of Revenues35.017.626.038.335.417.426.540.934.116.426.742.136.417.8
Percentage of Revenues mdu:ConstructionMaterials mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ContractingServices, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value28096219448303982464612978323840924774
Percentage of Revenues19.77.815.828.322.38.217.929.522.87.619.731.923.37.6
Percentage of Revenues19.77.815.828.322.38.217.929.522.87.619.731.923.37.6
Percentage of Revenues mdu:ContractingServices mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:InsideSpecialtyContracting, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value347355347352324372330317319299259217216233
Percentage of Revenues24.428.925.122.223.831.124.020.324.527.421.417.020.323.9
Percentage of Revenues24.428.925.122.223.831.124.020.324.527.421.417.020.323.9
Percentage of Revenues mdu:InsideSpecialtyContracting mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasGathering, mdu:Pipeline


Revenuesus-gaap:
Period End2020-09-302020-06-302020-03-312019-09-30
Value0.9731.1812.092.51
Percentage of Revenues0.10.10.20.2
Percentage of Revenues0.10.10.20.2
Percentage of Revenues mdu:NaturalGasGathering mdu:Pipeline100.0100.0100.0100.0

mdu:NaturalGasTransportation, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1112121110111111101111101011
Percentage of Revenues0.81.00.90.70.81.00.90.70.81.10.90.80.91.1
Percentage of Revenues0.81.00.90.70.81.00.90.70.81.10.90.80.91.1
Percentage of Revenues mdu:NaturalGasTransportation mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasTransportation, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value272927272725
Percentage of Revenues1.92.41.72.12.31.6
Percentage of Revenues1.92.41.72.12.31.6
Percentage of Revenues mdu:NaturalGasTransportation mdu:Pipeline100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.0570.0360.2920.4860.4120.3510.0610.0450.0090.0170.4930.0150.103-0.086
Percentage of Revenues0.00.00.00.00.00.00.00.00.00.00.00.00.0-0.0
Percentage of Revenues0.00.00.00.00.00.00.00.00.00.00.00.00.0-0.0
Percentage of Revenues mdu:OtherRevenues mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value9.4659.7738.6227.6637.7178.458.6569.388.4179.1218.7326.1588.4258.252
Percentage of Revenues0.70.80.60.50.60.70.60.60.60.80.70.50.80.8
Percentage of Revenues0.70.80.60.50.60.70.60.60.60.80.70.50.80.8
Percentage of Revenues mdu:OtherRevenues mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value2.7943.0092.9532.592.7112.4983.1822.7082.9233.9133.7583.2083.6143.999
Percentage of Revenues0.20.20.20.20.20.20.20.20.20.40.30.30.30.4
Percentage of Revenues0.20.20.20.20.20.20.20.20.20.40.30.30.30.4
Percentage of Revenues mdu:OtherRevenues mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value4.812.663.2033.3633.2415.534
Percentage of Revenues0.30.20.20.20.30.4
Percentage of Revenues0.30.20.20.20.30.4
Percentage of Revenues mdu:OtherRevenues mdu:Pipeline100.0100.0100.0100.0100.0100.0

mdu:OtherRevenues, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value3.3893.3413.0213.032.8612.9912.922.8842.9037.8432.7233.0842.7572.696
Percentage of Revenues0.20.30.20.20.20.20.20.20.20.70.20.20.30.3
Percentage of Revenues0.20.30.20.20.20.20.20.20.20.70.20.20.30.3
Percentage of Revenues mdu:OtherRevenues us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:OutsideSpecialtyContracting, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1651511711871601301391511331071091009587
Percentage of Revenues11.612.312.411.811.810.910.29.710.29.89.07.98.98.9
Percentage of Revenues11.612.312.411.811.810.910.29.710.29.89.07.98.98.9
Percentage of Revenues mdu:OutsideSpecialtyContracting mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value633265471822621262497869595227458743509213
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.8
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.8
Percentage of Revenues mdu:RevenueFromContractsWithCustomers mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value512505517540485500468467451406368317311320
Percentage of Revenues36.041.237.434.035.641.834.029.934.737.330.524.829.232.9
Percentage of Revenues36.041.237.434.035.641.834.029.934.737.330.524.829.232.9
Percentage of Revenues mdu:RevenueFromContractsWithCustomers mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value8487818675868887799279847788
Percentage of Revenues5.97.15.95.45.57.26.45.66.18.46.66.67.39.1
Percentage of Revenues5.97.15.95.45.57.26.45.66.18.46.66.67.39.1
Percentage of Revenues mdu:RevenueFromContractsWithCustomers mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value151347278951383242949213134626590128332
Percentage of Revenues10.628.320.16.010.127.121.45.910.131.821.97.112.134.1
Percentage of Revenues10.628.320.16.010.127.121.45.910.131.821.97.112.134.1
Percentage of Revenues mdu:RevenueFromContractsWithCustomers mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value279.87732271032
Percentage of Revenues1.90.82.02.00.92.1
Percentage of Revenues1.90.82.02.00.92.1
Percentage of Revenues mdu:RevenueFromContractsWithCustomers mdu:Pipeline100.0100.0100.0100.0100.0100.0

mdu:RevenueFromContractsWithCustomers, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.0280.0170.0150.024-0.1120.0180.0250.0220.0240.0190.0140.0470.090.058
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues mdu:RevenueFromContractsWithCustomers us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenuesOutOfScope, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1211131011111311121314111113
Percentage of Revenues0.91.01.00.70.81.01.00.70.91.31.20.91.11.3
Percentage of Revenues0.91.01.00.70.81.01.00.70.91.31.20.91.11.3
Percentage of Revenues mdu:RevenuesOutOfScope mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenuesOutOfScope, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.95-2.923-0.0640.9981.423-0.298-0.4362.2091.7030.5363.281.4450.546-1.338
Percentage of Revenues-0.1-0.2-0.00.10.1-0.0-0.00.10.10.00.30.10.1-0.1
Percentage of Revenues-0.1-0.2-0.00.10.1-0.0-0.00.10.10.00.30.10.1-0.1
Percentage of Revenues mdu:RevenuesOutOfScope mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenuesOutOfScope, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value2.4132.8866.433-0.4453.282.1140.6461.1672.401-4.3493.3661.7791.107-0.1
Percentage of Revenues0.20.20.5-0.00.20.20.00.10.2-0.40.30.10.1-0.0
Percentage of Revenues0.20.20.5-0.00.20.20.00.10.2-0.40.30.10.1-0.0
Percentage of Revenues mdu:RevenuesOutOfScope mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:RevenuesOutOfScope, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value0.0460.0360.0460.0440.0450.047
Percentage of Revenues0.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.00.00.0
Percentage of Revenues mdu:RevenuesOutOfScope mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:NaturalGasStorage, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value3.0944.0293.8853.1043.0463.044
Percentage of Revenues0.20.30.20.20.30.2
Percentage of Revenues0.20.30.20.20.30.2
Percentage of Revenues us-gaap:NaturalGasStorage mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value260442378210241418393209236439361200226424378206225433357192206385341185215427408211254491420192227424347184204395378212274477403223272
Percentage of Revenues18.336.027.413.217.735.028.613.418.140.329.915.721.343.532.516.321.146.235.215.919.742.632.114.521.846.535.115.423.347.135.514.921.445.532.115.821.146.335.518.529.552.938.719.930.0
Percentage of Revenues18.336.027.413.217.735.028.613.418.140.329.915.721.343.532.516.321.146.235.215.919.742.632.114.521.846.535.115.423.347.135.514.921.445.532.115.821.146.335.518.529.552.938.719.930.0
Percentage of Revenues us-gaap:RegulatedOperation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnregulatedOperation


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value116378510061377112177898413541067651848108083755178610658425046581016837519721109577049175411588395517631093833507733988763457686939656424639902634
Percentage of Revenues81.764.072.686.882.365.071.486.681.959.770.184.378.756.567.583.778.953.864.884.180.357.467.985.578.253.564.984.676.752.964.585.178.654.567.984.278.953.764.581.570.547.161.380.170.0
Percentage of Revenues81.764.072.686.882.365.071.486.681.959.770.184.378.756.567.583.778.953.864.884.180.357.467.985.578.253.564.984.676.752.964.585.178.654.567.984.278.953.764.581.570.547.161.380.170.0
Percentage of Revenues us-gaap:UnregulatedOperation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:RegulatedOperation, mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value838481877685888981928386788788917488838273826974647170686573676856646352576149575945
Percentage of Revenues5.96.95.95.55.67.26.45.76.28.56.96.77.49.07.67.27.09.48.26.87.19.26.65.86.57.86.05.06.07.15.75.35.46.95.45.56.85.45.46.45.35.0
Percentage of Revenues5.96.95.95.55.67.26.45.76.28.56.96.77.49.07.67.27.09.48.26.87.19.26.65.86.57.86.05.06.07.15.75.35.46.95.45.56.85.45.46.45.35.0
Percentage of Revenues us-gaap:RegulatedOperation mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value1533502859414132629593133342268921293322829213134226687112299264891323303059614637431577127331801163079216437094160
Percentage of Revenues10.828.520.66.010.427.321.46.010.331.422.27.212.234.124.27.212.336.526.27.310.833.124.97.013.536.026.37.013.435.926.66.012.035.66.812.136.18.017.741.18.417.7
Percentage of Revenues10.828.520.66.010.427.321.46.010.331.422.27.212.234.124.27.212.336.526.27.310.833.124.97.013.536.026.37.013.435.926.66.012.035.66.812.136.18.017.741.18.417.7
Percentage of Revenues us-gaap:RegulatedOperation mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedOperation, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value237.50227236.33125
Percentage of Revenues1.60.61.81.70.51.7
Percentage of Revenues1.60.61.81.70.51.7
Percentage of Revenues us-gaap:RegulatedOperation mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value633265471822621262497869595227458743509213423686501200398724541209425774495205400740434164388706418161641438149619375143612361
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.836.453.947.021.439.259.951.823.240.160.550.322.434.454.039.715.832.855.039.417.454.745.317.553.740.415.954.439.9
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.836.453.947.021.439.259.951.823.240.160.550.322.434.454.039.715.832.855.039.417.454.745.317.553.740.415.954.439.9
Percentage of Revenues us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnregulatedOperation, mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value524517531550496512482478464420383329323334356374336299250280285255237223211235246270275269255267277229246223218222192202210188
Percentage of Revenues36.942.138.434.736.442.835.030.635.638.631.725.730.334.230.629.431.531.924.623.227.428.222.317.521.425.621.219.725.125.921.620.826.124.721.023.125.619.320.722.418.720.8
Percentage of Revenues36.942.138.434.736.442.835.030.635.638.631.725.730.334.230.629.431.531.924.623.227.428.222.317.521.425.621.219.725.125.921.620.826.124.721.023.125.619.320.722.418.720.8
Percentage of Revenues us-gaap:UnregulatedOperation mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnregulatedOperation, mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value4.6432.4114.1034.2374.3246.576
Percentage of Revenues0.30.20.30.30.40.4
Percentage of Revenues0.30.20.30.30.40.4
Percentage of Revenues us-gaap:UnregulatedOperation mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:UnregulatedOperation, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value0.0280.0170.0150.024-0.1120.0180.0250.0220.0240.0190.0140.0470.090.0580.0550.1350.1990.320.2460.420.447
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:UnregulatedOperation us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value633265471822621262497869595227458743509213
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.8
Percentage of Revenues44.521.634.151.845.621.936.155.645.720.837.958.147.821.8
Percentage of Revenues mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ConstructionServices


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value524517531550496512482478464420383329323334
Percentage of Revenues36.942.138.434.736.442.835.030.635.638.631.725.730.334.2
Percentage of Revenues36.942.138.434.736.442.835.030.635.638.631.725.730.334.2
Percentage of Revenues mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:Electric


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value8384818776858889819283867887
Percentage of Revenues5.96.95.95.55.67.26.45.76.28.56.96.77.49.0
Percentage of Revenues5.96.95.95.55.67.26.45.76.28.56.96.77.49.0
Percentage of Revenues mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasDistribution


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value153350285941413262959313334226892129332
Percentage of Revenues10.828.520.66.010.427.321.46.010.331.422.27.212.234.1
Percentage of Revenues10.828.520.66.010.427.321.46.010.331.422.27.212.234.1
Percentage of Revenues mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:Pipeline


Revenuesus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value279.91332271032
Percentage of Revenues2.00.82.02.00.92.1
Percentage of Revenues2.00.82.02.00.92.1
Percentage of Revenues mdu:Pipeline100.0100.0100.0100.0100.0100.0

us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.0280.0170.0150.024-0.1120.0180.0250.0220.0240.0190.0140.0470.090.058
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues0.00.00.00.0-0.00.00.00.00.00.00.00.00.00.0
Percentage of Revenues us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:StatementBusinessSegments, us-gaap:SubsegmentsConsolidationItems

mdu:ConstructionMaterialsAndContracting, us-gaap:IntersubsegmentEliminations


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-145.78-46.716-107.299-234.693-164.719-44.104-113.605-231.078-145.925-35.14-102.092-204.04-125.567-34.27
Percentage of Revenues-10.2-3.8-7.7-14.8-12.1-3.7-8.2-14.8-11.2-3.2-8.4-15.9-11.8-3.5
Percentage of Revenues-10.2-3.8-7.7-14.8-12.1-3.7-8.2-14.8-11.2-3.2-8.4-15.9-11.8-3.5
Percentage of Revenues mdu:ConstructionMaterialsAndContracting us-gaap:IntersubsegmentEliminations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:SubsegmentsConsolidationItems

us-gaap:IntersubsegmentEliminations


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-145.78-46.716-107.299-234.693-164.719-44.104-113.605-231.078-145.925-35.14-102.092-204.04-125.567-34.27
Percentage of Revenues-10.2-3.8-7.7-14.8-12.1-3.7-8.2-14.8-11.2-3.2-8.4-15.9-11.8-3.5
Percentage of Revenues-10.2-3.8-7.7-14.8-12.1-3.7-8.2-14.8-11.2-3.2-8.4-15.9-11.8-3.5
Percentage of Revenues us-gaap:IntersubsegmentEliminations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Selling General And Administrative Expense

us-gaap:SellingGeneralAndAdministrativeExpense

us-gaap:SellingGeneralAndAdministrativeExpense


Selling
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value10778119641214102982195812121021702836996822600781973
Percentage of SellingGeneralAndAdministrativeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues75.766.169.676.575.568.669.677.578.364.469.177.877.261.567.076.5

us-gaap:SellingGeneralAndAdministrativeExpense us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation


Selling
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value89949389838793868887878283868880
Percentage of SellingGeneralAndAdministrativeExpense8.311.69.77.38.110.79.87.18.712.510.48.310.214.311.48.2
Percentage of Revenues6.37.76.75.66.17.36.85.56.88.07.26.57.98.87.66.3
Percentage of Revenues us-gaap:RegulatedOperation34.321.324.642.434.420.923.841.237.420.024.241.337.020.323.438.8

us-gaap:UnregulatedOperation


Selling
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value98871787011249467338651126932615749913738514692893
Percentage of SellingGeneralAndAdministrativeExpense91.788.490.392.791.989.390.292.991.387.589.691.789.885.788.691.8
Percentage of Revenues69.458.462.970.969.461.362.872.071.556.461.971.369.352.759.470.2
Percentage of Revenues us-gaap:UnregulatedOperation85.091.386.581.784.494.287.983.287.494.488.384.688.193.388.083.9

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value82988069805381257911785076837730759172786988671865336348633463446230614862846353638966186627698572707317780977747668740870617167709168286682690269016538655663596257619163036216611259815990
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidatedEntities

srt:ParentCompany


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value3226299042213962
Percentage of Assets40.138.960.462.6
Percentage of Assets40.138.960.462.6
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

us-gaap:Assets us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value179816841508123812201279127213051371137413821449
Percentage of Assets22.321.921.619.619.419.316.318.520.521.021.924.2
Percentage of Assets22.321.921.619.619.419.316.318.520.521.021.924.2
Percentage of Assets mdu:ConstructionMaterialsAndContracting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:ConstructionServices


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value818761604591513450454450429418387328
Percentage of Assets10.29.98.79.38.26.85.86.46.46.46.15.5
Percentage of Assets10.29.98.79.38.26.85.86.46.46.46.15.5
Percentage of Assets mdu:ConstructionServices100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:DiscontinuedOperations


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-31
Value1.221.8512.517
Percentage of Assets0.00.00.0
Percentage of Assets0.00.00.0
Percentage of Assets mdu:DiscontinuedOperations100.0100.0100.0

mdu:Electric


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value2123168016131470140613271030884760672643569
Percentage of Assets26.421.923.123.222.420.013.212.511.410.310.29.5
Percentage of Assets26.421.923.123.222.420.013.212.511.410.310.29.5
Percentage of Assets mdu:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:NaturalGasDistribution


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value230225742375220120992042193117861703167916321588
Percentage of Assets28.633.534.034.733.430.824.725.325.525.625.926.5
Percentage of Assets28.633.534.034.733.430.824.725.325.525.625.926.5
Percentage of Assets mdu:NaturalGasDistribution100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:PipelineandMidstream


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value703677616566550593655620
Percentage of Assets8.78.88.88.98.88.98.48.8
Percentage of Assets8.78.88.88.98.88.98.48.8
Percentage of Assets mdu:PipelineandMidstream100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CorporateAndOther


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value305303266261283287
Percentage of Assets3.83.93.84.14.54.3
Percentage of Assets3.83.93.84.14.54.3
Percentage of Assets us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value82988069805381257911785076837730759172786988671865336348633463446230614862846353638966186627698572707317780977747668740870617167709168286682690269016538655663596257619163036216611259815990
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-312017-12-31
Value3226299042213962
Percentage of LiabilitiesAndStockholdersEquity40.138.960.462.6
Percentage of Assets40.138.960.462.6
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value31983100307930122897283628472795266026052566252124512426242923532302231323162285223723822396237625422801313430833000290128232731267826632648274228202773277527912725268926922662262726082571
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets38.538.438.237.136.636.137.136.235.035.836.737.537.538.238.337.137.037.636.936.035.036.036.234.035.038.340.139.739.139.240.038.137.839.039.639.740.942.442.343.943.643.442.742.843.043.642.9

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value3079284725662429
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets38.237.136.738.3
Percentage of Assets srt:ParentCompany95.495.260.861.3

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-46.284-46.741-47.207-39.321-39.792-40.272-40.734-35.191-35.483-35.759-36.069-41.374-41.816-42.265-35.163
Percentage of StockholdersEquity-1.4-1.5-1.5-1.3-1.4-1.4-1.4-1.3-1.3-1.4-1.4-1.6-1.7-1.7-1.4
Percentage of Assets-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.6-0.7-0.6
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-0.761-0.873-0.984-1.096-1.207-1.319-1.43-1.541-1.653-1.764-2.161-2.044-2.136-2.231-1.934
Percentage of StockholdersEquity-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1
Percentage of Assets-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value0.0770.1040.1130.1680.190.1960.0620.0540.046-0.045-0.112-0.201-0.183-0.174-0.082
Percentage of StockholdersEquity0.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets0.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-46.968-47.51-48.078-40.249-40.809-41.395-42.102-36.678-37.09-37.568-38.342-43.619-44.135-44.86-37.334
Percentage of StockholdersEquity-1.5-1.5-1.6-1.3-1.4-1.5-1.5-1.3-1.4-1.4-1.5-1.7-1.8-1.8-1.5
Percentage of Assets-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.7-0.7-0.6
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value142213821371136613631360135513511315128412481247124512271233
Percentage of StockholdersEquity44.544.644.545.447.048.047.648.449.449.348.649.550.850.650.8
Percentage of Assets17.117.117.016.817.217.317.617.517.317.617.918.619.119.319.5
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value202201201201201201200200199198196196196195195
Percentage of StockholdersEquity6.36.56.56.76.97.17.17.27.57.67.77.88.08.18.1
Percentage of Assets2.42.52.52.52.52.62.62.62.62.72.82.93.03.13.1
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value162415671558148913771319133612831185116411631124105610511040
Percentage of StockholdersEquity50.850.650.649.447.646.546.945.944.644.745.344.643.143.342.8
Percentage of Assets19.619.419.418.317.416.817.416.615.616.016.716.716.216.616.4
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent

us-gaap:AssetsCurrent


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value1461132313371502139613731297146114441235118412141116104010691099101594297711441157105410211196128211611194141712761204111612541292114911281249123310781194113210711064116710359699891061
Percentage of AssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets17.616.416.618.517.717.516.918.919.017.016.918.117.116.416.917.316.315.315.618.018.115.915.417.117.615.915.318.216.616.315.817.518.216.816.918.117.916.518.217.817.117.218.516.715.916.517.7

us-gaap:AssetsCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Assets
Period End2020-12-312019-12-312018-12-312017-12-31
Value6567158166
Percentage of AssetsCurrent4.95.213.415.6
Percentage of Assets0.80.92.32.6
Percentage of Assets srt:ParentCompany2.02.33.84.2

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:CashAndCashEquivalentsAtCarryingValue


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value5755596664116666771495367415834374050465985908488144122812339083456611474497410191162118107136222366510617551105
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.70.70.70.80.81.50.90.90.90.70.81.00.60.90.50.60.60.80.70.91.31.41.31.32.01.71.03.01.21.10.60.91.61.10.71.11.51.42.51.91.72.23.50.61.11.82.90.00.0

us-gaap:CashAndCashEquivalentsAtCarryingValue us-gaap:ConsolidatedEntities

srt:ParentCompany


Cash
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value8.781122.2710.8434.1592.921
Percentage of CashAndCashEquivalentsAtCarryingValue14.718.54.22.49.03.5
Percentage of Assets0.10.20.00.00.10.0
Percentage of Assets srt:ParentCompany0.30.40.10.00.00.0

Receivables Net Current

us-gaap:ReceivablesNetCurrent

us-gaap:ReceivablesNetCurrent


Receivables
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value9037848731009920835836968890722722787743664727739661554630665637537590677627564693784731690713787734635678743654539646641566533583585502467531
Percentage of ReceivablesNetCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets10.99.710.912.411.610.610.912.511.79.910.311.711.410.511.511.710.69.010.010.510.08.18.99.78.67.78.910.19.59.310.111.010.49.310.110.89.58.39.910.19.18.69.39.48.27.88.9

us-gaap:ReceivablesNetCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Receivables
Period End2020-12-312019-12-312018-12-312017-12-31
Value4.8654.7279283
Percentage of ReceivablesNetCurrent0.60.612.811.5
Percentage of Assets0.10.11.31.3
Percentage of Assets srt:ParentCompany0.20.22.22.1

Inventory Net

us-gaap:InventoryNet

us-gaap:InventoryNet


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value316316291286302305278286325311287270278257226232249250238245265276253258314336300302331301282314345334317315333313274269277262252261260253249
Percentage of InventoryNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.83.93.63.53.83.93.63.74.34.34.14.04.34.13.63.74.04.13.83.94.24.23.83.74.34.63.93.94.34.14.04.44.94.94.74.64.84.84.24.24.44.24.04.24.34.24.2

Inventory Finished Goods

us-gaap:InventoryFinishedGoods

us-gaap:InventoryFinishedGoods


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value26242121222322232725221517161415161616151817151516152424252221232724313030283230333130
Percentage of InventoryFinishedGoods100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.30.30.30.30.30.30.30.40.30.30.20.30.30.20.20.30.30.30.20.30.30.20.20.20.20.30.30.30.30.30.30.40.40.50.40.40.40.50.50.50.50.5

Inventory Raw Materials And Supplies

us-gaap:InventoryRawMaterialsAndSupplies

us-gaap:InventoryRawMaterialsAndSupplies


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value27262526272622252826232324191820222218182021161922656571706869717475697572686164656157
Percentage of InventoryRawMaterialsAndSupplies100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.30.30.30.40.30.30.30.40.40.30.40.40.30.30.30.40.40.30.30.30.30.30.30.30.90.80.90.90.91.01.01.11.11.01.11.01.00.91.01.01.00.9

Other Assets Current

us-gaap:OtherAssetsCurrent

us-gaap:OtherAssetsCurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value7468446148601151401551511198852598189637948495057355681987672939949565868427185
Percentage of OtherAssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.90.80.50.80.60.81.51.82.12.11.71.30.80.91.31.41.01.30.80.80.80.90.50.81.11.31.00.91.21.30.70.80.81.00.61.01.2

us-gaap:OtherAssetsCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value1.6120.5011434
Percentage of OtherAssetsCurrent3.70.412.142.3
Percentage of Assets0.00.00.20.5
Percentage of Assets srt:ParentCompany0.00.00.30.9

Assets Noncurrent

us-gaap:AssetsNoncurrent

us-gaap:AssetsNoncurrent


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-30
Value683667466716662265146477131913221278125510861054105910521047112011291142124910771176148715591898
Percentage of AssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets82.483.683.481.582.382.517.217.116.817.315.615.716.216.616.517.718.118.619.917.018.422.523.527.2

us-gaap:AssetsNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Assets
Period End2020-12-312019-12-312018-12-312017-12-31
Value316034185180
Percentage of AssetsNoncurrent47.12.617.117.2
Percentage of Assets39.20.42.72.8
Percentage of Assets srt:ParentCompany98.01.24.44.6

Property Plant And Equipment Gross

us-gaap:PropertyPlantAndEquipmentGross

us-gaap:PropertyPlantAndEquipmentGross


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value84178288830082038063800879087746762575027397710269756842677066586591654465106588652668786817662765569299969394389390915088038651845483038107812980687798764675067394727172187163708568756766
Percentage of PropertyPlantAndEquipmentGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets101.4102.7103.1101.0101.9102.0102.9100.2100.4103.1105.9105.7106.8107.8106.9105.0105.8106.4103.6103.7102.1103.9102.994.990.2127.1124.1121.4122.5123.5124.7120.7119.2121.6121.3117.8116.9119.3116.6118.0118.2117.4114.5115.2115.9114.9112.9

us-gaap:PropertyPlantAndEquipmentGross us-gaap:PropertyPlantAndEquipmentByType, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

mdu:AggregateReserves, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value456455430406405404403394393395393
Percentage of PropertyPlantAndEquipmentGross5.55.85.86.06.25.94.24.54.95.25.4
Percentage of Assets5.75.96.26.46.56.15.25.65.96.06.2
Percentage of Assets mdu:AggregateReserves us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting0.00.00.00.00.00.00.00.00.00.00.0

mdu:GasStorage, us-gaap:RegulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value52504945454443
Percentage of PropertyPlantAndEquipmentGross0.60.60.70.70.70.60.5
Percentage of Assets0.70.70.70.70.70.70.6
Percentage of Assets mdu:GasStorage us-gaap:RegulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

mdu:General, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-31
Value198191
Percentage of PropertyPlantAndEquipmentGross2.42.4
Percentage of Assets2.52.5
Percentage of Assets mdu:General us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.0

us-gaap:BuildingAndBuildingImprovements, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value130122114102102697070736765
Percentage of PropertyPlantAndEquipmentGross1.61.51.61.51.61.00.70.80.90.90.9
Percentage of Assets1.61.61.61.61.61.00.91.01.11.01.0
Percentage of Assets us-gaap:BuildingAndBuildingImprovements us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:BuildingAndBuildingImprovements, us-gaap:UnregulatedOperation, mdu:ConstructionServices


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value4131292726231716161514
Percentage of PropertyPlantAndEquipmentGross0.50.40.40.40.40.30.20.20.20.20.2
Percentage of Assets0.50.40.40.40.40.40.20.20.20.20.2
Percentage of Assets us-gaap:BuildingAndBuildingImprovements us-gaap:UnregulatedOperation mdu:ConstructionServices0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ConstructionInProgress, us-gaap:RegulatedOperation, mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value6166161117624215014162
Percentage of PropertyPlantAndEquipmentGross0.70.82.21.71.00.61.61.60.8
Percentage of Assets0.80.92.31.91.00.61.92.00.9
Percentage of Assets us-gaap:ConstructionInProgress us-gaap:RegulatedOperation mdu:Electric0.00.00.00.00.00.00.00.00.0

us-gaap:ConstructionInProgress, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value163921191920594671
Percentage of PropertyPlantAndEquipmentGross0.20.50.30.30.30.30.60.50.9
Percentage of Assets0.20.50.30.30.30.30.80.71.1
Percentage of Assets us-gaap:ConstructionInProgress us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.00.00.00.00.00.00.00.0

us-gaap:ConstructionInProgress, us-gaap:RegulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value46225.91517167.5495.386
Percentage of PropertyPlantAndEquipmentGross0.60.30.10.30.30.10.1
Percentage of Assets0.60.30.10.30.30.10.1
Percentage of Assets us-gaap:ConstructionInProgress us-gaap:RegulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

us-gaap:ConstructionInProgress, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2325227.7516188.70913118.0854.879
Percentage of PropertyPlantAndEquipmentGross0.30.30.30.10.20.30.10.20.10.10.1
Percentage of Assets0.30.30.30.10.30.30.10.20.20.10.1
Percentage of Assets us-gaap:ConstructionInProgress us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ConstructionInProgress, us-gaap:UnregulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value0.0040.1540.0860.0170.0130.0890.691
Percentage of PropertyPlantAndEquipmentGross0.00.00.00.00.00.00.0
Percentage of Assets0.00.00.00.00.00.00.0
Percentage of Assets us-gaap:ConstructionInProgress us-gaap:UnregulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

us-gaap:ElectricDistribution, us-gaap:RegulatedOperation, mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value464443430415398375343308282255243
Percentage of PropertyPlantAndEquipmentGross5.65.65.86.16.15.53.53.53.53.33.4
Percentage of Assets5.85.86.26.66.35.74.44.44.23.93.9
Percentage of Assets us-gaap:ElectricDistribution us-gaap:RegulatedOperation mdu:Electric0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ElectricGenerationEquipment, us-gaap:RegulatedOperation, mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value113311391131103410361003627570580546538
Percentage of PropertyPlantAndEquipmentGross13.714.415.315.315.914.76.56.57.27.27.5
Percentage of Assets14.114.816.216.316.515.18.08.18.78.38.5
Percentage of Assets us-gaap:ElectricGenerationEquipment us-gaap:RegulatedOperation mdu:Electric0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ElectricTransmission, us-gaap:RegulatedOperation, mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value524445302296284255229196190179161
Percentage of PropertyPlantAndEquipmentGross6.35.64.14.44.43.82.42.22.32.32.2
Percentage of Assets6.55.84.34.74.53.92.92.82.82.72.6
Percentage of Assets us-gaap:ElectricTransmission us-gaap:RegulatedOperation mdu:Electric0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:GasDistribution, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value23022133198118311718162414811384132912571223
Percentage of PropertyPlantAndEquipmentGross27.727.026.827.126.423.815.315.716.416.416.9
Percentage of Assets28.627.828.428.927.324.519.019.619.919.219.4
Percentage of Assets us-gaap:GasDistribution us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:GasTransmission, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-31
Value104104
Percentage of PropertyPlantAndEquipmentGross1.31.3
Percentage of Assets1.31.4
Percentage of Assets us-gaap:GasTransmission us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.0

us-gaap:GasTransmission, us-gaap:RegulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value665636585516490460449
Percentage of PropertyPlantAndEquipmentGross8.08.17.97.67.56.84.6
Percentage of Assets8.38.38.48.27.86.95.8
Percentage of Assets us-gaap:GasTransmission us-gaap:RegulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

us-gaap:Land, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1321271099594123125125126126124
Percentage of PropertyPlantAndEquipmentGross1.61.61.51.41.51.81.31.41.61.71.7
Percentage of Assets1.71.71.61.51.51.91.61.81.91.92.0
Percentage of Assets us-gaap:Land us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:Land, us-gaap:UnregulatedOperation, mdu:ConstructionServices


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value7.2187.1465.2165.2165.3466.465.2654.8214.7234.7064.526
Percentage of PropertyPlantAndEquipmentGross0.10.10.10.10.10.10.10.10.10.10.1
Percentage of Assets0.10.10.10.10.10.10.10.10.10.10.1
Percentage of Assets us-gaap:Land us-gaap:UnregulatedOperation mdu:ConstructionServices0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:Land, us-gaap:UnregulatedOperation, us-gaap:CorporateAndOther


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value2.6482.6482.6482.8372.837
Percentage of PropertyPlantAndEquipmentGross0.00.00.00.00.0
Percentage of Assets0.00.00.00.00.0
Percentage of Assets us-gaap:Land us-gaap:UnregulatedOperation us-gaap:CorporateAndOther0.00.00.00.00.0

us-gaap:MachineryAndEquipment, us-gaap:UnregulatedOperation, mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value128411801090947930
Percentage of PropertyPlantAndEquipmentGross15.514.914.714.014.3
Percentage of Assets16.015.415.615.014.8
Percentage of Assets us-gaap:MachineryAndEquipment us-gaap:UnregulatedOperation mdu:ConstructionMaterialsAndContracting0.00.00.00.00.0

us-gaap:MachineryAndEquipment, us-gaap:UnregulatedOperation, mdu:ConstructionServices


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value163156145137132
Percentage of PropertyPlantAndEquipmentGross2.02.02.02.02.0
Percentage of Assets2.02.02.12.22.1
Percentage of Assets us-gaap:MachineryAndEquipment us-gaap:UnregulatedOperation mdu:ConstructionServices0.00.00.00.00.0

us-gaap:NaturalGasStorage, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-31
Value3331
Percentage of PropertyPlantAndEquipmentGross0.40.4
Percentage of Assets0.40.4
Percentage of Assets us-gaap:NaturalGasStorage us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:RegulatedOperation, mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value13913212211710710910599978683
Percentage of PropertyPlantAndEquipmentGross1.71.71.71.71.71.61.11.11.21.11.2
Percentage of Assets1.71.71.71.81.71.61.31.41.51.31.3
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:RegulatedOperation mdu:Electric0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:RegulatedOperation, mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value213515496468440431364345360311285
Percentage of PropertyPlantAndEquipmentGross2.66.56.76.96.86.33.83.94.44.14.0
Percentage of Assets2.76.77.17.47.06.54.74.95.44.84.5
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:RegulatedOperation mdu:NaturalGasDistribution0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:RegulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value49484541404039
Percentage of PropertyPlantAndEquipmentGross0.60.60.60.60.60.60.4
Percentage of Assets0.60.60.70.60.70.60.5
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:RegulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:UnregulatedOperation, mdu:ConstructionServices


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value8.824177.7166.7747.105118.2217.5088.8939.19810
Percentage of PropertyPlantAndEquipmentGross0.10.20.10.10.10.20.10.10.10.10.1
Percentage of Assets0.10.20.10.10.10.20.10.10.10.10.2
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:UnregulatedOperation mdu:ConstructionServices0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:UnregulatedOperation, mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value7.1649.5189.5779.6499.89.82711
Percentage of PropertyPlantAndEquipmentGross0.10.10.10.10.20.10.1
Percentage of Assets0.10.10.10.20.20.10.2
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:UnregulatedOperation mdu:PipelineandMidstream0.00.00.00.00.00.00.0

us-gaap:OtherCapitalizedPropertyPlantAndEquipment, us-gaap:UnregulatedOperation, us-gaap:CorporateAndOther


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value3432252846
Percentage of PropertyPlantAndEquipmentGross0.40.40.30.40.7
Percentage of Assets0.40.40.40.40.7
Percentage of Assets us-gaap:OtherCapitalizedPropertyPlantAndEquipment us-gaap:UnregulatedOperation us-gaap:CorporateAndOther0.00.00.00.00.0

us-gaap:PropertyPlantAndEquipmentGross us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value202819101768156015491553152915101504149914861514
Percentage of PropertyPlantAndEquipmentGross24.424.223.923.023.822.815.817.218.619.620.622.4
Percentage of Assets25.224.925.324.624.723.419.621.422.522.923.625.3
Percentage of Assets mdu:ConstructionMaterialsAndContracting112.8113.4117.2125.9127.0121.5120.3115.7109.8109.2107.5104.5

mdu:ConstructionServices


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value220213188177171163144134130124122116
Percentage of PropertyPlantAndEquipmentGross2.72.72.52.62.62.41.51.51.61.61.71.7
Percentage of Assets2.72.82.72.82.72.51.81.92.01.92.01.9
Percentage of Assets mdu:ConstructionServices27.028.031.230.033.436.231.829.930.429.831.735.3

mdu:Electric


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value23232227214819821888178614571315115010681027941
Percentage of PropertyPlantAndEquipmentGross28.028.229.029.329.026.215.014.914.214.014.213.9
Percentage of Assets28.929.030.731.330.127.018.718.617.216.316.315.7
Percentage of Assets mdu:Electric109.4132.6133.1134.8134.3134.6141.4148.8151.3158.8159.6165.3

mdu:NaturalGasDistribution


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value286826882499231921792076190417761689156815081456
Percentage of PropertyPlantAndEquipmentGross34.634.033.834.333.530.519.720.220.820.520.921.5
Percentage of Assets35.635.035.836.634.731.324.425.225.323.923.924.3
Percentage of Assets mdu:NaturalGasDistribution124.6104.4105.2105.4103.8101.698.699.599.293.492.591.7

mdu:PipelineandMidstream


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value821834764700672758818789
Percentage of PropertyPlantAndEquipmentGross9.910.510.310.310.311.18.49.0
Percentage of Assets10.210.910.911.110.711.410.511.2
Percentage of Assets mdu:PipelineandMidstream116.8123.1124.0123.7122.1127.9124.8127.2

us-gaap:CorporateAndOther


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value373528314949
Percentage of PropertyPlantAndEquipmentGross0.50.40.40.50.80.7
Percentage of Assets0.50.50.40.50.80.7
Percentage of Assets us-gaap:CorporateAndOther12.311.610.611.917.417.2

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value31293096313331153064303929912944290328582818279627582725269126672638260925782583255125432506245524444233416640924011395438723796370936783608354634783419336133073236317431033056300029352872
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets37.738.438.938.338.738.738.938.138.239.340.341.642.242.942.542.042.342.441.040.739.938.437.835.233.657.953.352.652.353.454.853.052.353.954.051.450.452.351.352.051.751.349.249.249.149.147.9

Amortization Of Intangible Assets

us-gaap:AmortizationOfIntangibleAssets

us-gaap:AmortizationOfIntangibleAssets


Amortization
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1200000.01500000.02200000.02100000.02700000.02000000.0800000.0500000.0500000.0600000.0300000.0300000.0300000.0400000.0300000.0500000.0600000.0600000.0600000.0600000.0600000.0600000.0500000.0600000.0700000.0700000.0700000.0700000.01000000.0800000.01000000.01200000.01000000.0800000.0900000.01000000.01000000.0900000.0700000.01100000.01000000.0900000.0800000.01300000.01100000.0
Percentage of AmortizationOfIntangibleAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value52875192516650874998496849174801472246434578430642174117407939913953393439314004397443344311417141115066552653465378519549314855474446244498458245904379428541994158409641154107408439393894
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets63.764.364.262.663.263.364.062.162.263.865.564.164.664.964.462.963.564.062.663.062.265.565.059.756.669.270.868.870.170.169.867.766.967.767.366.466.567.065.466.066.566.265.366.166.865.965.0

Long Term Investments

us-gaap:LongTermInvestments

us-gaap:LongTermInvestments


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value17316716515815414514814414514413814314013813713313112912512612412111911811911811711511611311210810610610310299113109109116117
Percentage of LongTermInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.12.12.01.92.01.91.91.91.92.02.02.12.12.22.22.12.12.12.02.01.91.81.81.71.61.61.51.51.51.51.61.51.51.61.51.51.41.71.71.71.91.9

us-gaap:LongTermInvestments us-gaap:ConsolidatedEntities

srt:ParentCompany


Long
Period End2020-12-312019-12-312018-12-312017-12-31
Value52467676
Percentage of LongTermInvestments31.531.155.055.8
Percentage of Assets0.60.61.11.2
Percentage of Assets srt:ParentCompany1.61.51.81.9

Goodwill

us-gaap:Goodwill

us-gaap:Goodwill


Goodwill
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value717714714712708713681681679679664640642631631631631631631641641641635635635635635636636636636636636636636636635635634634634634634634634634629
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets8.78.98.98.89.09.18.98.88.99.39.59.59.810.010.010.010.110.310.110.110.09.79.69.18.78.78.18.28.38.69.08.99.09.39.59.29.29.79.710.010.110.310.110.210.410.610.5

us-gaap:Goodwill us-gaap:BusinessAcquisition

mdu:A2020Acquisition


Goodwillus-gaap:
Period End2020-12-31
Value33
Percentage of Goodwill4.7
Percentage of Assets0.4
Percentage of Assets mdu:A2020Acquisition0.0

mdu:A2020AcquisitionMemberDomain


Goodwillus-gaap:
Period End2020-09-302020-06-302020-03-31
Value312732
Percentage of Goodwill4.43.94.5
Percentage of Assets0.40.30.4
Percentage of Assets mdu:A2020AcquisitionMemberDomain0.00.00.0

mdu:A2021Acquisition


Goodwillus-gaap:
Period End2021-06-30
Value2.9
Percentage of Goodwill0.4
Percentage of Assets0.0
Percentage of Assets mdu:A2021Acquisition0.0

us-gaap:Goodwill us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Goodwillus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-31
Value228226226223223223217217223223209184186176176176176176176176176176176176176176176176176176176176176176176176176176176176176176176176176175
Percentage of Goodwill31.931.631.631.431.631.431.931.933.033.031.528.929.127.927.927.927.927.927.927.527.527.527.827.827.827.827.827.727.727.727.727.727.727.727.727.727.727.727.827.827.827.827.827.827.827.9
Percentage of Assets2.82.82.82.82.82.82.82.82.93.13.02.72.92.82.82.82.82.92.82.82.82.72.72.52.42.42.32.32.32.42.52.52.52.62.62.62.62.72.72.82.82.82.82.82.92.9
Percentage of Assets mdu:ConstructionMaterialsAndContracting0.00.012.60.00.00.012.90.00.00.013.90.00.00.014.20.00.00.014.40.00.00.013.80.00.00.013.90.00.00.013.50.00.00.012.90.00.00.012.80.00.00.012.70.00.012.1

mdu:ConstructionServices


Goodwillus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-31
Value143143143143139144118118109109109109109109109109109109109109109109103103103103103104104104104104104104104104103103103103103103102102102100
Percentage of Goodwill20.020.020.020.119.620.217.417.416.216.216.517.117.117.417.417.417.417.417.417.117.117.116.316.316.316.316.316.416.416.416.416.416.416.416.416.416.316.316.216.216.216.216.216.216.215.9
Percentage of Assets1.71.81.81.81.81.81.51.51.41.51.61.61.71.71.71.71.81.81.71.71.71.71.61.51.41.41.31.31.41.41.51.51.51.51.61.51.51.61.61.61.61.71.61.71.71.7
Percentage of Assets mdu:ConstructionServices0.00.017.50.00.00.015.60.00.00.018.10.00.00.018.60.00.00.021.40.00.00.022.90.00.00.022.80.00.00.023.10.00.00.024.30.00.00.024.70.00.00.026.50.00.030.4

Intangible Assets Net Excluding Goodwill

us-gaap:IntangibleAssetsNetExcludingGoodwill

us-gaap:IntangibleAssetsNetExcludingGoodwill


Intangible
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value23232526313415151111104.3184.193.4653.8374.2094.7855.3475.9256.5297.167.8037.3427.9088.5069.1669.841011121314151617181819202223242526262628
Percentage of IntangibleAssetsNetExcludingGoodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.30.30.30.40.40.20.20.10.20.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.20.20.20.20.20.30.30.30.30.30.30.40.40.40.40.40.40.5

us-gaap:IntangibleAssetsNetExcludingGoodwill us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:CustomerRelationships


Intangible
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value20212121242511128.9729.3159.1852.5782.3961.6611.8662.0722.4432.8353.2283.6214.0374.4654.134.524.915.3265.7546.1946.5767.087.5848.0898.5959.0999.60910101011111212131314
Percentage of IntangibleAssetsNetExcludingGoodwill88.387.886.181.978.875.876.778.679.279.884.959.757.247.948.649.251.153.054.555.556.457.256.357.257.758.158.558.558.457.657.957.456.155.856.156.255.354.154.353.152.752.652.752.354.4
Percentage of Assets0.20.30.30.30.30.30.20.20.10.10.10.00.00.00.00.00.00.00.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.20.20.20.20.20.20.20.2
Percentage of Assets us-gaap:CustomerRelationships0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NoncompeteAgreements


Intangible
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1.4151.51.6321.7652.1452.3011.4821.5511.3811.4490.6490.6950.6690.5880.6250.6610.6980.7350.7720.8080.8450.8820.7540.7770.8280.9050.9821.0591.1441.2451.3461.481.6291.7971.912.0382.0292.1652.3142.4632.6232.7872.983.1743.372
Percentage of IntangibleAssetsNetExcludingGoodwill6.06.36.46.76.86.79.710.012.212.46.016.116.017.016.315.714.613.713.012.411.811.310.39.89.79.910.010.010.210.110.310.510.611.011.211.310.910.811.111.111.211.411.812.212.9
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.10.1
Percentage of Assets us-gaap:NoncompeteAgreements0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherIntangibleAssets


Intangible
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1.3281.4171.9153.0184.5226.02.0741.7720.970.9160.9811.0451.1251.2161.3461.4761.6441.7771.9252.12.2782.4562.4582.6112.7682.9353.1043.3433.5463.9714.1694.5235.0885.4225.615.8596.3077.0137.2197.9798.4078.7528.9749.2698.573
Percentage of IntangibleAssetsNetExcludingGoodwill5.75.97.511.414.317.513.611.48.67.89.124.226.835.135.135.134.433.232.532.231.831.533.533.032.532.031.531.531.532.331.832.133.233.232.832.533.835.134.635.936.035.935.535.532.7
Percentage of Assets0.00.00.00.00.10.10.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.1
Percentage of Assets us-gaap:OtherIntangibleAssets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OperatingLeaseRightOfUseAsset


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-06-302018-03-31
Value1121161201201151141151181181070.00.00.0
Percentage of OperatingLeaseRightOfUseAsset100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0
Percentage of Assets1.41.41.51.51.51.51.51.51.61.50.00.00.0

us-gaap:OperatingLeaseRightOfUseAsset us-gaap:ConsolidatedEntities

srt:ParentCompany


Operating
Period End2020-12-312019-12-31
Value0.0560.153
Percentage of OperatingLeaseRightOfUseAsset0.00.1
Percentage of Assets0.00.0
Percentage of Assets srt:ParentCompany0.00.0

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent

us-gaap:OtherAssetsNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value144150144147154153506504466455408408409412407419416409415360360359366355362326325247249246251298297295299314324312311262253254257260255249231
Percentage of OtherAssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.71.91.81.81.91.96.66.56.26.35.96.16.36.56.46.66.76.76.65.75.65.45.55.15.04.54.23.23.33.33.64.24.24.34.54.64.74.84.74.14.14.14.14.24.24.23.9

us-gaap:OtherAssetsNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value2834180175
Percentage of OtherAssetsNoncurrent20.06.844.143.1
Percentage of Assets0.40.42.62.8
Percentage of Assets srt:ParentCompany0.91.14.34.4

Accounts Payable Current

us-gaap:AccountsPayableCurrent

us-gaap:AccountsPayableCurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value431379426436433384403378356352358339330267312304279239279281275260310292272259382410424399404437411375388402379321337305304267301
Percentage of AccountsPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.24.75.35.45.54.95.34.94.74.85.15.15.14.24.94.84.53.94.54.44.33.94.74.23.83.64.95.35.55.45.76.15.85.55.85.85.54.95.14.84.94.34.8

us-gaap:AccountsPayableCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Accounts
Period End2020-12-312019-12-312018-12-312017-12-31
Value2.1352.9815047
Percentage of AccountsPayableCurrent0.50.714.015.0
Percentage of Assets0.00.00.70.7
Percentage of Assets srt:ParentCompany0.10.11.21.2

Contract With Customer Liability Current

us-gaap:ContractWithCustomerLiabilityCurrent

us-gaap:ContractWithCustomerLiabilityCurrent


Contract
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value14614215815815815314212090869398908071
Percentage of ContractWithCustomerLiabilityCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.81.82.02.02.02.01.91.61.21.21.31.51.41.31.1

Dividends Payable Current

us-gaap:DividendsPayableCurrent

us-gaap:DividendsPayableCurrent


Dividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value424242414141414040393938383838373737373636363635353535343433333232320.1713131313130303030
Percentage of DividendsPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.60.60.60.60.50.50.50.50.40.40.50.50.50.50.50.00.50.50.50.50.50.50.50.5

us-gaap:DividendsPayableCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Dividends
Period End2020-12-312019-12-312018-12-312017-12-31
Value42413938
Percentage of DividendsPayableCurrent100.0100.0100.0100.0
Percentage of Assets0.50.50.60.6
Percentage of Assets srt:ParentCompany1.31.40.91.0

Liabilities Current

us-gaap:LiabilitiesCurrent

us-gaap:LiabilitiesCurrent


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value944900963106699982486610339121062986725800764812856693618669744702761947941108098696893879674578484586591785010251024910898764723654768727640662667
Percentage of LiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets11.411.212.013.112.610.511.313.412.014.614.110.812.312.012.813.511.110.110.711.711.011.514.313.514.913.512.412.110.410.111.111.812.213.412.714.914.813.913.712.011.610.612.211.710.511.111.1

us-gaap:LiabilitiesCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-312017-12-31
Value6867396263
Percentage of LiabilitiesCurrent7.27.840.232.4
Percentage of Assets0.90.95.74.2
Percentage of Assets srt:ParentCompany2.12.29.46.6

Long Term Debt Current

us-gaap:LongTermDebtCurrent

us-gaap:LongTermDebtCurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value1.5491.5521.5551.55816161665512512513.915109149148148834343935898238
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.20.20.20.90.73.53.60.11.72.42.32.31.30.70.71.50.91.53.6

Operating Lease Liability Current

us-gaap:OperatingLeaseLiabilityCurrent

us-gaap:OperatingLeaseLiabilityCurrent


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-06-302018-03-31
Value313233333131313231300.00.00.0
Percentage of OperatingLeaseLiabilityCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0
Percentage of Assets0.40.40.40.40.40.40.40.40.40.40.00.00.0

us-gaap:OperatingLeaseLiabilityCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Operating
Period End2020-12-312019-12-31
Value0.040.096
Percentage of OperatingLeaseLiabilityCurrent0.10.3
Percentage of Assets0.00.0
Percentage of Assets srt:ParentCompany0.00.0

Other Liabilities Current

us-gaap:OtherLiabilitiesCurrent

us-gaap:OtherLiabilitiesCurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value188201198226182172221225218213221221208204186184181188184191196189171157164179172173179185171171185205204233244255259226224227222
Percentage of OtherLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.32.52.52.82.32.22.92.92.92.93.23.33.23.22.92.92.93.12.93.03.12.92.62.32.32.52.22.22.32.52.42.42.63.03.13.43.53.94.03.63.63.73.5

us-gaap:OtherLiabilitiesCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value6.8817.695436
Percentage of OtherLiabilitiesCurrent3.53.524.519.8
Percentage of Assets0.10.10.80.6
Percentage of Assets srt:ParentCompany0.20.31.30.9

Taxes Payable Current

us-gaap:TaxesPayableCurrent

us-gaap:TaxesPayableCurrent


Taxes
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value7888889680584853465541504757421085574485945504544384845105486174808955465446517077454956
Percentage of TaxesPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.91.11.11.21.00.70.60.70.60.80.60.80.70.90.71.70.91.20.80.90.70.80.70.60.50.70.61.40.60.81.11.11.30.80.70.80.70.81.11.20.70.80.9

us-gaap:TaxesPayableCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Taxes
Period End2020-12-312019-12-312018-12-312017-12-31
Value4.0561.2532413
Percentage of TaxesPayableCurrent4.62.658.932.2
Percentage of Assets0.10.00.40.2
Percentage of Assets srt:ParentCompany0.10.00.60.3

Liabilities Noncurrent

us-gaap:LiabilitiesNoncurrent

us-gaap:LiabilitiesNoncurrent


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value41554068401040454013418917421720169016641578156015381528152615411555155715521515152015391531151615441615176616151662161915781602159316171573163216731640159614571439143314081390133512841265
Percentage of LiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets50.150.449.849.850.753.422.722.322.322.922.623.223.524.124.124.325.025.324.723.923.823.323.121.721.222.122.620.821.721.922.422.422.523.723.523.624.225.124.322.923.023.222.322.421.921.521.1

us-gaap:LiabilitiesNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-312017-12-31
Value7875672657
Percentage of LiabilitiesNoncurrent2.04.442.643.1
Percentage of Assets1.01.09.610.4
Percentage of Assets srt:ParentCompany2.42.515.916.6

Long Term Debt

us-gaap:LongTermDebt

us-gaap:LongTermDebt


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-31
Value23372253221322702281245522432246237921982108171417901796
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets28.227.927.527.928.831.329.229.131.330.230.227.128.527.1

us-gaap:LongTermDebt dei:LegalEntity, us-gaap:LongtermDebtType

mdu:CascadeNaturalGas, us-gaap:SeniorNotes


Long
Period End2020-10-302020-06-152019-12-312019-06-13
Value25507575
Percentage of LongTermDebt0.00.03.30.0
Percentage of Assets0.00.01.00.0
Percentage of Assets mdu:CascadeNaturalGas us-gaap:SeniorNotes0.00.00.00.0

mdu:WbiEnergyTransmissionInc, us-gaap:SeniorNotes


Long
Period End2020-12-312020-12-162019-12-312019-12-16
Value1952517045
Percentage of LongTermDebt8.80.07.60.0
Percentage of Assets2.40.02.20.0
Percentage of Assets mdu:WbiEnergyTransmissionInc us-gaap:SeniorNotes0.00.00.00.0

us-gaap:LongTermDebt us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value233722532213227022812455224322462379219821081915185217791714174017611703179019011987192718712275237621892094221021872105185420112006
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0100.00.00.00.0100.00.00.00.0104.20.00.00.00.00.00.00.00.00.00.0
Percentage of Assets28.227.927.527.928.831.329.229.131.330.230.228.528.428.027.127.428.327.728.529.931.129.128.232.632.729.926.828.428.528.426.328.128.3
Percentage of Assets us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LongTermDebt us-gaap:LongtermDebtType

us-gaap:CommercialPaper


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-31
Value2972181252142902652222814334733388826262
Percentage of LongTermDebt12.79.75.79.412.710.89.912.518.221.616.05.214.63.5
Percentage of Assets3.62.71.62.63.73.42.93.65.76.54.81.44.20.9
Percentage of Assets us-gaap:CommercialPaper0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LineOfCredit


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value484395911125989311162110
Percentage of LongTermDebt2.11.94.34.00.510.64.01.40.52.95.2
Percentage of Assets0.60.51.21.10.13.31.20.40.10.91.6
Percentage of Assets us-gaap:LineOfCredit0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LoansPayable


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value8.48.48.48.49.19.19.1209209209209
Percentage of LongTermDebt0.40.40.40.40.40.40.49.38.89.59.9
Percentage of Assets0.10.10.10.10.10.10.12.72.82.93.0
Percentage of Assets us-gaap:LoansPayable0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:MediumTermNotes


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-31
Value3535353550505050505050505050
Percentage of LongTermDebt1.51.61.61.52.22.02.22.22.12.32.42.92.82.8
Percentage of Assets0.40.40.40.40.60.60.70.60.70.70.70.80.80.8
Percentage of Assets us-gaap:MediumTermNotes0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NotesPayableToBanks


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-31
Value3.2323.2824.0342828282926262625242424
Percentage of LongTermDebt0.10.10.21.21.21.21.31.21.11.21.21.51.41.4
Percentage of Assets0.00.00.10.30.40.40.40.30.30.40.40.40.40.4
Percentage of Assets us-gaap:NotesPayableToBanks0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-31
Value19501950195019001900185018501655165613811381149914371616
Percentage of LongTermDebt83.486.588.183.783.375.382.573.769.662.865.587.580.390.0
Percentage of Assets23.524.224.223.424.023.624.121.421.819.019.823.722.924.4
Percentage of Assets us-gaap:SeniorNotes0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent

us-gaap:LongTermDebtNoncurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312011-12-312010-12-31
Value2335225122112268226524382226218023271946185619111743163015661592167716591746180819281759155712851433
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets28.127.927.527.928.631.129.028.230.726.726.628.526.725.724.725.126.927.027.828.530.226.623.519.622.7

Deferred Income Tax Liabilities Net

us-gaap:DeferredIncomeTaxLiabilitiesNet

us-gaap:DeferredIncomeTaxLiabilitiesNet


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value538528516533516515506487457444430405362346347652668666668662666
Percentage of DeferredIncomeTaxLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets6.56.66.46.66.56.66.66.36.06.16.26.05.65.55.510.310.710.810.610.410.4

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-31
Value201818
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent100.0100.0100.0
Percentage of Assets0.30.20.3
Percentage of Assets us-gaap:OverfundedPlan us-gaap:QualifiedPlan us-gaap:OtherPostretirementBenefitPlansDefinedBenefit0.00.00.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value53558391102
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent259.0296.5444.10.00.0
Percentage of Assets0.70.71.21.41.6
Percentage of Assets us-gaap:UnderfundedPlan us-gaap:QualifiedPlan us-gaap:PensionPlansDefinedBenefit0.00.00.00.00.0

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value320329327295286290115211471145114211481154117511811179889887890883821820811811755755810813727736720718794810814818834833842827710711731736718708680674
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.94.14.13.63.63.715.014.815.115.716.417.218.018.618.614.014.214.514.112.912.812.312.210.810.411.110.49.49.69.710.211.111.411.912.212.112.112.912.611.211.411.811.711.611.611.411.3

us-gaap:OtherLiabilitiesNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value7875507509
Percentage of OtherLiabilitiesNoncurrent23.96.644.243.2
Percentage of Assets1.01.07.38.0
Percentage of Assets srt:ParentCompany2.42.512.012.9

Operating Lease Liability Noncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-06-302018-03-31
Value818486878483838687760.00.00.0
Percentage of OperatingLeaseLiabilityNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0
Percentage of Assets1.01.01.11.11.11.11.11.11.11.10.00.00.0

us-gaap:OperatingLeaseLiabilityNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Operating
Period End2020-12-312019-12-31
Value0.0160.056
Percentage of OperatingLeaseLiabilityNoncurrent0.00.1
Percentage of Assets0.00.0
Percentage of Assets srt:ParentCompany0.00.0

Lessee Operating Lease Liability Payments Due Year Two

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo


Lessee
Period End2020-12-31
Value25
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo100.0
Percentage of Assets0.3

Lessee Operating Lease Liability Payments Due Year Three

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree


Lessee
Period End2020-12-31
Value16
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearThree100.0
Percentage of Assets0.2

Lessee Operating Lease Liability Payments Due Year Four

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour


Lessee
Period End2020-12-31
Value12
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour100.0
Percentage of Assets0.2

Lessee Operating Lease Liability Payments Due Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive


Lessee
Period End2020-12-31
Value7852000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFive100.0
Percentage of Assets0.1

Lessee Operating Lease Liability Payments Due After Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive


Lessee
Period End2020-12-31
Value48
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive100.0
Percentage of Assets0.6

Operating Lease Liability

us-gaap:OperatingLeaseLiability

us-gaap:OperatingLeaseLiability


Operating
Period End2020-12-31
Value120
Percentage of OperatingLeaseLiability100.0
Percentage of Assets1.5

Lessee Operating Lease Liability Payments Due

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue


Lessee
Period End2020-12-31
Value147
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue100.0
Percentage of Assets1.8

Lessee Operating Lease Liability Undiscounted Excess Amount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount


Lessee
Period End2020-12-31
Value26
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount100.0
Percentage of Assets0.3

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value31983100307930122897283628472795266026052566252124512426242923532302231323162285223723822396237625422801313430833000290128232731267826632648274228202773277527912725268926922662262726082571
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets38.538.438.237.136.636.137.136.235.035.836.737.537.538.238.337.137.037.636.936.035.036.036.234.035.038.340.139.739.139.240.038.137.839.039.639.740.942.442.343.943.643.442.742.843.043.642.9

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value3079284725662429
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets38.237.136.738.3
Percentage of Assets srt:ParentCompany95.495.260.861.3

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-46.284-46.741-47.207-39.321-39.792-40.272-40.734-35.191-35.483-35.759-36.069-41.374-41.816-42.265-35.163
Percentage of StockholdersEquity-1.4-1.5-1.5-1.3-1.4-1.4-1.4-1.3-1.3-1.4-1.4-1.6-1.7-1.7-1.4
Percentage of Assets-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.6-0.7-0.6
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-0.761-0.873-0.984-1.096-1.207-1.319-1.43-1.541-1.653-1.764-2.161-2.044-2.136-2.231-1.934
Percentage of StockholdersEquity-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1
Percentage of Assets-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value0.0770.1040.1130.1680.190.1960.0620.0540.046-0.045-0.112-0.201-0.183-0.174-0.082
Percentage of StockholdersEquity0.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets0.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-46.968-47.51-48.078-40.249-40.809-41.395-42.102-36.678-37.09-37.568-38.342-43.619-44.135-44.86-37.334
Percentage of StockholdersEquity-1.5-1.5-1.6-1.3-1.4-1.5-1.5-1.3-1.4-1.4-1.5-1.7-1.8-1.8-1.5
Percentage of Assets-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.7-0.7-0.6
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value142213821371136613631360135513511315128412481247124512271233
Percentage of StockholdersEquity44.544.644.545.447.048.047.648.449.449.348.649.550.850.650.8
Percentage of Assets17.117.117.016.817.217.317.617.517.317.617.918.619.119.319.5
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value202201201201201201200200199198196196196195195
Percentage of StockholdersEquity6.36.56.56.76.97.17.17.27.57.67.77.88.08.18.1
Percentage of Assets2.42.52.52.52.52.62.62.62.62.72.82.93.03.13.1
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value162415671558148913771319133612831185116411631124105610511040
Percentage of StockholdersEquity50.850.650.649.447.646.546.945.944.644.745.344.643.143.342.8
Percentage of Assets19.619.419.418.317.416.817.416.615.616.016.716.716.216.616.4
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Stockholders Equity Including Portion Attributable To Noncontrolling Interest

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest


Stockholders
Period End2020-12-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value30792847256625212451242624292353230223132316228522372495252025142686293432493158306429492855275026942674264827422820277327752692
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets38.237.136.737.537.538.238.337.137.037.636.936.035.037.738.036.037.040.141.640.640.039.840.438.438.039.239.639.740.942.442.342.7

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2020-12-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-312010-12-31
Value-48.078-42.102-38.342-43.619-44.135-44.86-37.334-35.341-35.789-36.185-35.733-37.891-38.206-38.582-37.148-39.844-40.246-40.924-42.103-37.032-37.198-38.205-48.721-47.001-31.261
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest-1.6-1.5-1.5-1.7-1.8-1.8-1.5-1.5-1.6-1.6-1.5-1.7-1.7-1.5-1.5-1.6-1.5-1.4-1.3-1.2-1.2-1.3-1.8-1.7-1.2
Percentage of Assets-0.6-0.5-0.5-0.6-0.7-0.7-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.7-0.7-0.5
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2020-12-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value13711355124812471245122712331232123112311232123012071056103910351026
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest44.547.648.649.550.850.650.852.453.553.253.248.837.137.039.237.338.1
Percentage of Assets17.017.617.918.619.119.319.519.419.820.019.618.615.515.015.515.816.3
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2020-12-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value201200196196196195195195195195195195194189189189188
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest6.57.17.77.88.08.18.18.38.58.58.57.86.06.67.26.87.0
Percentage of Assets2.52.62.82.93.03.13.13.13.13.23.13.02.52.72.82.93.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2020-12-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value155813361163112410561051104096491491191299617621603145715861497
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest50.646.945.344.643.143.342.841.039.739.439.439.554.256.155.057.155.6
Percentage of Assets19.417.416.716.716.216.616.415.214.714.814.515.022.622.721.824.223.8
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value202201201201201201200200199198196196196195195195195195195195195195195195195195194194194191189189189189189189189189189189189189188188188188188
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.42.52.52.52.52.62.62.62.62.72.82.93.03.13.13.13.13.23.13.13.13.03.02.82.72.72.52.52.52.62.72.62.72.82.82.72.72.92.93.03.03.13.03.03.13.23.1

us-gaap:CommonStockValue us-gaap:ConsolidatedEntities

srt:ParentCompany


Common
Period End2020-12-312019-12-312018-12-312017-12-31
Value201200196195
Percentage of CommonStockValue100.0100.0100.0100.0
Percentage of Assets2.52.62.83.1
Percentage of Assets srt:ParentCompany6.26.74.74.9

Additional Paid In Capital Common Stock

us-gaap:AdditionalPaidInCapitalCommonStock

us-gaap:AdditionalPaidInCapitalCommonStock


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value14221382137113661363136013551351131512841248124712451227123312321231123112321231123012291230122812201214120712001186111010561041104010381039103810361035103510341033
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets17.117.117.016.817.217.317.617.517.317.617.918.619.119.319.519.419.820.019.619.419.318.618.617.616.816.615.515.415.515.015.014.514.715.215.515.015.015.815.816.316.5

us-gaap:AdditionalPaidInCapitalCommonStock us-gaap:ConsolidatedEntities

srt:ParentCompany


Additional
Period End2020-12-312019-12-312018-12-312017-12-31
Value1371135512481233
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0
Percentage of Assets17.017.617.919.5
Percentage of Assets srt:ParentCompany42.545.329.631.1

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value16241567155814891377131913361283118511641163112410561051104096491491191288483898499698011551421176217131645162516031546149414801457155016121589158615561523150914971439140713881377
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets19.619.419.418.317.416.817.416.615.616.016.716.716.216.616.415.214.714.814.513.913.114.915.014.015.919.422.622.021.521.922.721.621.121.721.822.523.424.324.224.524.324.423.823.123.023.223.0

us-gaap:RetainedEarningsAccumulatedDeficit us-gaap:ConsolidatedEntities

srt:ParentCompany


Retained
Period End2020-12-312019-12-312018-12-312017-12-31
Value1558133611631040
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0
Percentage of Assets19.417.416.716.4
Percentage of Assets srt:ParentCompany48.344.727.626.3

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value-46968000.0-47510000.0-48078000.0-40249000.0-40809000.0-41395000.0-42102000.0-36678000.0-37090000.0-37568000.0-38342000.0-43619000.0-44135000.0-44860000.0-37334000.0-35341000.0-35789000.0-36185000.0-35733000.0-37891000.0-38206000.0-38582000.0-37148000.0-39844000.0-40246000.0-40924000.0-42103000.0-37032000.0-37198000.0-37538000.0-38205000.0-56937000.0-56821000.0-56615000.0-48721000.0-46448000.0-29575000.0-52930000.0-47001000.0-588000.0-32268000.0-53112000.0-31261000.0496000.0-463000.0635000.0-20833000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.7-0.7-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.6-0.5-0.5-0.5-0.5-0.5-0.8-0.8-0.8-0.7-0.7-0.4-0.8-0.7-0.0-0.5-0.9-0.50.0-0.00.0-0.3

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap:ConsolidatedEntities

srt:ParentCompany


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-31
Value-48078000.0-42102000.0-38342000.0-37334000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0
Percentage of Assets-0.6-0.5-0.5-0.6
Percentage of Assets srt:ParentCompany-1.5-1.4-0.9-0.9

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount

srt:RestatementAdjustment


Accumulated
Period End2020-12-31
Value-2700000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax5.6
Percentage of Assets-0.0
Percentage of Assets srt:RestatementAdjustment0.0

Stock Issued During Period Value New Issues

us-gaap:StockIssuedDuringPeriodValueNewIssues

us-gaap:StockIssuedDuringPeriodValueNewIssues


Stock
Period End2021-06-302021-03-312020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value34193.413630380.1830.0170.0047.3954.6359.8645.229127754
Percentage of StockIssuedDuringPeriodValueNewIssues100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Stock
Period End2021-06-302021-03-312020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value33193.2983429370.1750.017
Percentage of StockIssuedDuringPeriodValueNewIssues96.996.696.796.396.096.195.60.096.0
Percentage of Assets0.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stock
Period End2021-06-302021-03-312020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1.0890.6720.1121.3371.2221.5060.0080.00.714
Percentage of StockIssuedDuringPeriodValueNewIssues3.13.43.33.74.03.94.40.04.0
Percentage of Assets0.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value879528622018279339225-24.4791.5841821407010517613252861851735745258208799421219273137313195971362551544912421515713312018016811885
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues6.17.820.713.913.46.624.614.5-1.90.115.111.06.610.815.110.45.09.218.314.45.55.024.416.38.010.318.314.16.713.126.415.29.214.723.613.25.114.720.213.714.413.417.314.913.010.2

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-160.173-106.327-168.409-165.296-94.068-202.47-155.236-143.567-144.949-160.109-349.577-139.079-122.007-100.244-115.22-76.421-68.11645-50.779-76.774-98.007-79.535161-141.638-242.165-160.213-260.693-57.777-205.408-380.313-177.295-194.827-239.726-170.813-235.595-238.767-257.148-156.442-138.743-106.901-136.748-82.15321-98.284-208.596-122.287
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues-11.3-8.7-12.2-10.4-6.9-16.9-11.3-9.2-11.1-14.7-28.9-10.9-11.5-10.3-9.9-6.0-6.44.9-5.0-6.4-9.4-8.815.2-11.1-24.6-17.4-22.4-4.2-18.8-36.5-15.0-15.2-22.6-18.3-21.8-20.3-26.6-18.3-13.0-9.3-14.7-9.12.0-8.7-23.0-14.6

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value756.254-124.721-53.357-140.212173-184.482-87.397191154153233418-63.647-58.6794.476-127.5-148.717-122.3013540-424.519-122.496185106-103.4948.5138281-156.812-48.99518359-44.97656217-39.977-32.205-39.153-25.422-124.411-15.53-99.55749-31.162
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues5.30.5-9.0-3.4-10.314.5-13.4-5.614.714.112.71.93.21.9-5.5-4.60.4-13.6-14.6-10.13.44.5-40.0-9.618.811.5-8.90.612.727.0-13.2-3.817.36.3-4.24.822.5-4.7-3.0-3.4-2.7-13.8-1.5-8.85.5-3.7

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DeferredIncomeTaxExpenseBenefit


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value4.6559.843-18.21131.0681.8131426101217386.254-2.068-8.646-11.484-4.961-0.332-0.703-4.954-3.2946.902-12.335-12.238185-160.63350-23.13524354026-24.87344-47.813-36.677443238192634-4.73735278.226
Percentage of DeferredIncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Depreciation Depletion And Amortization

us-gaap:DepreciationDepletionAndAmortization

us-gaap:DepreciationDepletionAndAmortization


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value7373727271696865635958555352525251515354546062575495951031039998999593989183858688838483848178
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Increase Decrease In Accounts Payable

us-gaap:IncreaseDecreaseInAccountsPayable

us-gaap:IncreaseDecreaseInAccountsPayable


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value38-41.965-3.175.73837-24.10517111.0420.3564.9540.40747-31.864-4.0841834-23.38-8.4758.17544-37.205-12.8511798-53.334-23.0581.27-11.752-11.525-10.7336.87754-35.091-15.4592822-29.851-4.226-4.8418-21.875-1.9493221-34.795
Percentage of IncreaseDecreaseInAccountsPayable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Increase Decrease In Inventories

us-gaap:IncreaseDecreaseInInventories

us-gaap:IncreaseDecreaseInInventories


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-0.28325-2.36-16.695-3.06129-6.851-38.78214218.011-8.6111729-7.088-15.62-0.10313-6.586-19.0360.891223.181-53.6852344-1.415-28.7042919-28.89-31.48510191.948-17.9812038458.15-15.52-13.6347.837-0.123-6.244-6.198
Percentage of IncreaseDecreaseInInventories100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value879528622018279339225-24.4791.5841821407010517613252861851735745258208799421219273137313195971362551544912421515713312018016811885
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues6.17.820.713.913.46.624.614.5-1.90.115.111.06.610.815.110.45.09.218.314.45.55.024.416.38.010.318.314.16.713.126.415.29.214.723.613.25.114.720.213.714.413.417.314.913.010.2

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1005211215399259513761407810743421158741376582-109.1532452-139.448-229.604-305.91784103545691844656-60.986-29.67154356163454288614841
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.04.28.19.67.32.16.98.84.73.86.58.44.14.39.96.93.94.06.56.9-10.52.74.9-10.9-23.3-33.37.27.54.95.47.76.64.46.1-5.6-2.55.64.25.75.64.84.88.55.45.45.0

us-gaap:NetIncomeLoss us-gaap:DerivativeInstrumentRisk, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:InterestRateContract, us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.112-0.111-0.112-0.111-0.112-0.111-0.111-0.112-0.111-0.3970.117-0.092-0.095-0.092
Percentage of NetIncomeLoss-0.1-0.2-0.1-0.1-0.1-0.4-0.1-0.1-0.2-1.00.1-0.1-0.2-0.2
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:InterestRateContract us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmount

srt:RestatementAdjustment


Net
Period End2020-12-312020-03-31
Value4.4-6.7
Percentage of NetIncomeLoss3.9-26.7
Percentage of Revenues0.3-0.6
Percentage of Revenues srt:RestatementAdjustment0.087.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.594-0.612-0.639-0.61-0.599-0.572-0.723-0.4-0.399-0.735-0.781-0.567-0.827-0.54
Percentage of NetIncomeLoss-0.6-1.2-0.6-0.4-0.6-2.3-0.8-0.3-0.6-1.8-1.0-0.5-1.9-1.3
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.0-0.0-0.1-0.1-0.0-0.1-0.1
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.457-0.466-0.509-0.471-0.48-0.462-0.608-0.292-0.276-0.31-0.864-0.442-0.449-0.418
Percentage of NetIncomeLoss-0.5-0.9-0.5-0.3-0.5-1.8-0.6-0.2-0.4-0.8-1.1-0.4-1.0-1.0
Percentage of Revenues-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.025-0.035-0.018-0.028-0.0070.001-0.0040.004-0.012-0.028-0.034-0.033-0.034-0.03
Percentage of NetIncomeLoss-0.0-0.1-0.0-0.0-0.00.0-0.00.0-0.0-0.1-0.0-0.0-0.1-0.1
Percentage of Revenues-0.0-0.0-0.0-0.0-0.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Revenues us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-03-31
Value1005215399251376140107434237
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.04.29.67.32.18.84.73.88.44.14.34.0
Percentage of Revenues us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-160.173-106.327-168.409-165.296-94.068-202.47-155.236-143.567-144.949-160.109-349.577-139.079-122.007-100.244-115.22-76.421-68.11645-50.779-76.774-98.007-79.535161-141.638-242.165-160.213-260.693-57.777-205.408-380.313-177.295-194.827-239.726-170.813-235.595-238.767-257.148-156.442-138.743-106.901-136.748-82.15321-98.284-208.596-122.287
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues-11.3-8.7-12.2-10.4-6.9-16.9-11.3-9.2-11.1-14.7-28.9-10.9-11.5-10.3-9.9-6.0-6.44.9-5.0-6.4-9.4-8.815.2-11.1-24.6-17.4-22.4-4.2-18.8-36.5-15.0-15.2-22.6-18.3-21.8-20.3-26.6-18.3-13.0-9.3-14.7-9.12.0-8.7-23.0-14.6

Payments To Acquire Productive Assets

us-gaap:PaymentsToAcquireProductiveAssets

us-gaap:PaymentsToAcquireProductiveAssets


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value150111144165109139153141147133222134105105119787172848310411514012816618933324821017926021724218824324121417415711414282
Percentage of PaymentsToAcquireProductiveAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value756.254-124.721-53.357-140.212173-184.482-87.397191154153233418-63.647-58.6794.476-127.5-148.717-122.3013540-424.519-122.496185106-103.4948.5138281-156.812-48.99518359-44.97656217-39.977-32.205-39.153-25.422-124.411-15.53-99.55749-31.162
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues5.30.5-9.0-3.4-10.314.5-13.4-5.614.714.112.71.93.21.9-5.5-4.60.4-13.6-14.6-10.13.44.5-40.0-9.618.811.5-8.90.612.727.0-13.2-3.817.36.3-4.24.822.5-4.7-3.0-3.4-2.7-13.8-1.5-8.85.5-3.7

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:ProceedsFromIssuanceOfLongTermDebt


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302010-12-312010-09-30
Value789316-100.275-47.621248296-66.2512271412091161391017.375693.84259-32.713-45.848161226186.482171149-66.2672301313091046338112671002990.00.0-5.72.401-65.193
Percentage of ProceedsFromIssuanceOfLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0100.0100.0100.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt


Repayments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-5.155374-88.52612536301664652175366373390-54.002147793931164423108-16.0255449207535816741147676514508.297168-2.603-161.8328021-6.731-1.2930.479
Percentage of RepaymentsOfLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Payments Of Dividends

us-gaap:PaymentsOfDividends

us-gaap:PaymentsOfDividends


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value4242414141414040393938383838373737373636363635353535343433333232320.17164313131215-30.85-92.39630208-29.802-89.29429
Percentage of PaymentsOfDividends100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Payments For Repurchase Of Common Stock

us-gaap:PaymentsForRepurchaseOfCommonStock

us-gaap:PaymentsForRepurchaseOfCommonStock


Payments
Period End2021-06-302021-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value06701000.000000005020000.00001684000.00000
Percentage of PaymentsForRepurchaseOfCommonStock0.0100.00.00.00.00.00.00.00.0100.00.00.00.0100.00.00.00.00.0

Deferred Tax Liabilities

us-gaap:DeferredTaxLiabilities

us-gaap:DeferredTaxLiabilities


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312011-12-312010-12-31
Value5165064303476686876821048931
Percentage of DeferredTaxLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Assets Valuation Allowance

us-gaap:DeferredTaxAssetsValuationAllowance

us-gaap:DeferredTaxAssetsValuationAllowance


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value111313119.1178.990.00.00.0
Percentage of DeferredTaxAssetsValuationAllowance100.0100.0100.0100.0100.0100.00.00.00.0

mdu:ContractwithCustomerAssetNetCurrentChange

mdu:ContractwithCustomerAssetNetCurrentChange


Contractwith
Period End2021-06-302021-03-312020-12-31
Value393.198-31.613
Percentage of ContractwithCustomerAssetNetCurrentChange100.0100.0100.0

mdu:ContractwithCustomerAssetsandLiabilitiesNetChange

mdu:ContractwithCustomerAssetsandLiabilitiesNetChange


Contractwith
Period End2021-06-302021-03-312020-12-312018-12-312018-09-302018-06-302018-03-31
Value3618-31.283-33.304-19.348360.601
Percentage of ContractwithCustomerAssetsandLiabilitiesNetChange100.0100.0100.0100.0100.0100.0100.0

mdu:ContractwithCustomerLiabilityCurrentChange

mdu:ContractwithCustomerLiabilityCurrentChange


Contractwith
Period End2021-06-302021-03-312020-12-31
Value3.288-15.775-0.32
Percentage of ContractwithCustomerLiabilityCurrentChange100.0100.0100.0

mdu:ContractwithCustomerLiabilityNoncurrentChange

mdu:ContractwithCustomerLiabilityNoncurrentChange


Contractwith
Period End2021-06-302021-03-312020-12-31
Value-11000.0119000.0-10000.0
Percentage of ContractwithCustomerLiabilityNoncurrentChange100.0100.0100.0

mdu:DefinedBenefitPlanNetPeriodicBenefitCostAmountCapitalized us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

mdu:DefinedBenefitPlanNetPeriodicBenefitCostAmountCapitalized

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-44000.0-39000.0-50000.0-39000.0-35000.0-32000.0-29000.0-26000.0-27000.0-31000.0-25000.0-46000.0-43000.0-40000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCostAmountCapitalized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

mdu:DefinedBenefitPlanNetPeriodicBenefitCostIncludingAmountCapitalized us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

mdu:DefinedBenefitPlanNetPeriodicBenefitCostIncludingAmountCapitalized

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-752000.0-752000.0-540000.0-401000.0-620000.0-600000.0-430000.0-431000.0-512000.0-348000.0-307000.0-307000.0-520000.0-93000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCostIncludingAmountCapitalized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value-435000.0-435000.0-171000.0-171000.0-417000.075000.0635000.0634000.01260000.08000.0211000.0211000.0-170000.0591000.0507000.0509000.0240000.0778000.0627000.0627000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCostIncludingAmountCapitalized57.857.831.742.667.3-12.5-147.7-147.1-246.1-2.3-68.7-68.732.7-635.50.00.00.00.00.00.0

mdu:DepreciationAndAmortizationRatePercent dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:DepreciationAndAmortizationRatePercent

mdu:IntermountainGas, mdu:PendingRateCase, us-gaap:GasDistribution, mdu:IPUC


Depreciation
Period End2021-01-12
Value3.0
Percentage of DepreciationAndAmortizationRatePercent100.0

mdu:DepreciationAndAmortizationRequestedRateAmendedPercent dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:DepreciationAndAmortizationRequestedRateAmendedPercent

mdu:IntermountainGas, mdu:PendingRateCase, us-gaap:GasDistribution, mdu:IPUC


Depreciation
Period End2021-06-03
Value2.4
Percentage of DepreciationAndAmortizationRequestedRateAmendedPercent100.0

mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmendedAmount dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmendedAmount

mdu:IntermountainGas, mdu:PendingRateCase, us-gaap:GasDistribution, mdu:IPUC


Depreciation
Period End2021-06-03
Value-3800000.0
Percentage of DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmendedAmount100.0

mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmount dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmount

mdu:IntermountainGas, mdu:PendingRateCase, us-gaap:GasDistribution, mdu:IPUC


Depreciation
Period End2021-01-12
Value-2900000.0
Percentage of DepreciationAndAmortizationRequestedRateIncreaseDecreaseAmount100.0

mdu:DepreciationAndAmortizationRequestedRatePercent dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:DepreciationAndAmortizationRequestedRatePercent

mdu:IntermountainGas, mdu:PendingRateCase, us-gaap:GasDistribution, mdu:IPUC


Depreciation
Period End2021-01-12
Value2.6
Percentage of DepreciationAndAmortizationRequestedRatePercent100.0

mdu:EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease

mdu:EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease


Environmental
Period End2020-09-30
Value11
Percentage of EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease100.0

mdu:EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease us-gaap:EnvironmentalRemediationSite

mdu:BremertonWAManufacturedGasPlantSite


Environmental
Period End2020-09-30
Value11
Percentage of EnvironmentalMattersAccrualForSiteRemediationPeriodIncrease100.0

mdu:RenewableResourceCostAdjustmentRateTariff dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:RenewableResourceCostAdjustmentRateTariff

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:NDPSC, us-gaap:SubsequentEvent


Renewable
Period End2021-02-01
Value14
Percentage of RenewableResourceCostAdjustmentRateTariff100.0

mdu:TotalInfrastructureRider dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:TotalInfrastructureRider

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:SDPUC, us-gaap:SubsequentEvent


Total
Period End2021-05-01
Value1000000.0
Percentage of TotalInfrastructureRider100.0

mdu:TotalTransmissionCostAdjustmentRider dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:TotalTransmissionCostAdjustmentRider

mdu:MontanaDakotaUtilitiesCo., mdu:PendingRateCase, mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Total
Period End2021-07-15
Value14
Percentage of TotalTransmissionCostAdjustmentRider100.0

mdu:TotalTransmissionCostAdjustmentRider dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:MontanaDakotaUtilitiesCo., mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Total
Period End2020-11-01
Value15
Percentage of TotalTransmissionCostAdjustmentRider0.0

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:SDPUC, us-gaap:SubsequentEvent


Total
Period End2021-05-01
Value1.0
Percentage of TotalTransmissionCostAdjustmentRider0.0

mdu:TransmissionCapitalProjectsIncreaseDecrease dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:TransmissionCapitalProjectsIncreaseDecrease

mdu:MontanaDakotaUtilitiesCo., mdu:PendingRateCase, mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Transmission
Period End2021-07-15
Value5100000.0
Percentage of TransmissionCapitalProjectsIncreaseDecrease100.0

mdu:TransmissionCapitalProjectsIncreaseDecrease dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:MontanaDakotaUtilitiesCo., mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Transmission
Period End2020-11-01
Value3300000.0
Percentage of TransmissionCapitalProjectsIncreaseDecrease0.0

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:SDPUC, us-gaap:SubsequentEvent


Transmission
Period End2021-05-01
Value274000.0
Percentage of TransmissionCapitalProjectsIncreaseDecrease0.0

mdu:TransmissionFormulaRevenueRequirement dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:TransmissionFormulaRevenueRequirement

mdu:MontanaDakotaUtilitiesCo., mdu:Electric, mdu:MISO, us-gaap:SubsequentEvent


Transmission
Period End2021-01-01
Value12
Percentage of TransmissionFormulaRevenueRequirement100.0

mdu:UnderRecoveredBalanceTransmissionCostAdjustmentRider dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:UnderRecoveredBalanceTransmissionCostAdjustmentRider

mdu:MontanaDakotaUtilitiesCo., mdu:COVID19, mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Under
Period End2020-11-01
Value1600000.0
Percentage of UnderRecoveredBalanceTransmissionCostAdjustmentRider100.0

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions


Adjustments
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value6.152.5743.3122.6182.251.7421.7421.6171.6491.2931.2941.090.9850.7610.6330.9961.4280.940.951.0651.4231.1591.228-0.1211.9341.4611.461.336-9.0111.2771.2771.176
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Adjustments
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value6.152.5743.3122.6182.251.7421.7421.6171.251.2931.2941.2230.6460.8740.7211.134
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions100.0100.0100.0100.0100.0100.0100.0100.075.8100.0100.0112.265.6114.8113.9113.9

us-gaap:AllowanceForDoubtfulAccountsReceivableRecoveries

us-gaap:AllowanceForDoubtfulAccountsReceivableRecoveries


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value299000.0342000.0278000.0289000.0338000.0
Percentage of AllowanceForDoubtfulAccountsReceivableRecoveries100.0100.0100.0100.0100.0

us-gaap:AllowanceForDoubtfulAccountsReceivableRecoveries us-gaap:StatementBusinessSegments

mdu:Electric


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value100000.0129000.075000.088000.0109000.0
Percentage of AllowanceForDoubtfulAccountsReceivableRecoveries33.437.727.030.432.2

mdu:NaturalGasDistribution


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value199000.0213000.0203000.0201000.0229000.0
Percentage of AllowanceForDoubtfulAccountsReceivableRecoveries66.662.373.069.667.8

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1424000.02669000.01307000.01399000.01265000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs100.0100.0100.0100.0100.0

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value232000.0273000.0229000.044000.068000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs16.310.217.53.15.4

mdu:ConstructionServices


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value64000.0401000.0117000.0454000.073000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs4.515.09.032.55.8

mdu:Electric


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value341000.0888000.0269000.0224000.0500000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs23.933.320.616.039.5

mdu:NaturalGasDistribution


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value787000.01107000.0692000.0677000.0624000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs55.341.552.948.449.3

us-gaap:CapitalExpendituresIncurredButNotYetPaid

us-gaap:CapitalExpendituresIncurredButNotYetPaid


Capital
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value1120-7.158-3.2539.06827117.056-0.343277.7613.6091416126.4655.2375.2120.1524.111-11.78330362.032-40.667546.9540.543065-18.5178.573-15.163927.569-7.8692451106.1099.15315
Percentage of CapitalExpendituresIncurredButNotYetPaid100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value2.852-4.4531.712-52.16850-4.96622-4.227
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-0.033-0.025-0.687-0.2920.038-0.4341.043-1.3141.242-0.507-1.222-2.944-0.0070.231568.174303.3043232-2.975-22.5547734870.0-0.3821.032-0.4990.0080.027-0.1060.0570.3034.146-6.568-0.151-0.107-0.102-0.081-0.125-0.366-0.3190.00.00.0
Percentage of CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:CommonStockDividendsPerShareDeclared

us-gaap:CommonStockDividendsPerShareDeclared


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.21250.21250.21250.20750.20750.20750.20750.20250.20250.20250.20250.19750.19750.19750.19750.19250.19250.19250.19250.18750.18750.18750.18750.18250.18250.18250.18250.17750.17750.17750.17750.17250.17250.17250.17250.16750.16750.16750.16750.16250.16250.16250.16250.15750.15750.1575
Percentage of CommonStockDividendsPerShareDeclared100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiabilityRevenueRecognized

us-gaap:ContractWithCustomerLiabilityRevenueRecognized


Contract
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value211230.91532892.57.52256-0.6101652
Percentage of ContractWithCustomerLiabilityRevenueRecognized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod

us-gaap:ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod


Contract
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value27340.03431193.821201840-8.72.63.1
Percentage of ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-6000.0-6000.0-72000.0-71000.0-142000.0-2000.0-271000.0-27000.042000.00-160000.0-160000.0-82000.0-238000.0
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value-2004000.0-2004000.0-1793000.0-1793000.0-1723000.0-1863000.0-1388000.0-1387000.0-1418000.0-1355000.0-1751000.0-1751000.0-1721000.0-1782000.0-1588000.0-1589000.0-1385000.0-1793000.0-1555000.0-1553000.0
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses33400.033400.02490.32525.41213.493150.0512.25137.0-3376.20.01094.41094.42098.8748.70.00.00.00.00.00.0

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-349000.0-349000.0-350000.0-349000.0-402000.0-297000.0-532000.0-289000.0-228000.0-252000.0-348000.0-349000.0-348000.0-349000.0
Percentage of DefinedBenefitPlanAmortizationOfPriorServiceCostCredit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.2751.2751.2551.1151.4011.2481.2011.2011.1821.221.2161.2171.2661.167
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value4.8944.8944.9874.9875.2144.7614.5594.5593.9985.125.1885.1885.3794.9985.1335.1325.2345.0295.2315.231
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets383.8383.8397.4447.3372.2381.5379.6379.6338.2419.7426.6426.3424.9428.30.00.00.00.00.00.0

us-gaap:DefinedBenefitPlanInterestCost us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanInterestCost

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.4660.4660.610.6090.6270.5910.7470.7460.7130.780.7240.7250.6720.778
Percentage of DefinedBenefitPlanInterestCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value2.4552.4553.0233.0233.0742.9733.8063.8063.843.7733.6483.6483.4883.8074.0524.0524.0894.0144.3034.305
Percentage of DefinedBenefitPlanInterestCost526.8526.8495.6496.4490.3503.0509.5510.2538.6483.7503.9503.2519.0489.30.00.00.00.00.00.0

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-796000.0-791000.0-590000.0-440000.0-655000.0-632000.0-459000.0-457000.0-539000.0-379000.0-332000.0-353000.0-563000.0-133000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnderfundedPlan, us-gaap:QualifiedPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value-435000.0-435000.0-171000.0-171000.0-417000.075000.0635000.0634000.01260000.08000.0211000.0211000.0-170000.0591000.0442000.0444000.0167000.0671000.0530000.0545000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost54.655.029.038.963.7-11.9-138.3-138.7-233.8-2.1-63.6-59.830.2-444.40.00.00.00.00.00.0

us-gaap:UnfundedPlan, us-gaap:NonqualifiedPlan, us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value769000.0769000.0956000.01000000.0900000.01000000.01046000.01100000.01100000.01100000.01089000.01100000.01100000.01100000.01166000.01200000.01100000.01200000.01215000.01300000.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost-96.6-97.2-162.0-227.3-137.4-158.2-227.9-240.7-204.1-290.2-328.0-311.6-195.4-827.10.00.00.00.00.00.0

us-gaap:DefinedBenefitPlanServiceCost us-gaap:RetirementPlanFundingStatus, us-gaap:RetirementPlanTaxStatus, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanServiceCost

us-gaap:OverfundedPlan, us-gaap:QualifiedPlan, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value400000.0400000.0383000.0383000.0414000.0352000.0285000.0286000.0227000.0344000.0373000.0374000.0340000.0407000.0
Percentage of DefinedBenefitPlanServiceCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DividendsCommonStockCash

us-gaap:DividendsCommonStockCash


Dividends
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value4342414141404040403838383937373737363636363535353534343334323232
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DividendsCommonStockCash us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Dividends
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value43424141414040404038383839373737
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GoodwillPurchaseAccountingAdjustments

us-gaap:GoodwillPurchaseAccountingAdjustments


Goodwill
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value-9000.04013000.0-3613000.000-6669000.0000
Percentage of GoodwillPurchaseAccountingAdjustments100.0100.0100.00.00.0100.00.00.00.0

us-gaap:GoodwillPurchaseAccountingAdjustments us-gaap:BusinessAcquisition

mdu:A2020AcquisitionMemberDomain


Goodwill
Period End2020-09-30
Value4000000.0
Percentage of GoodwillPurchaseAccountingAdjustments99.7

us-gaap:GoodwillPurchaseAccountingAdjustments us-gaap:StatementBusinessSegments

mdu:ConstructionServices


Goodwill
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value04013000.0-3613000.0000000
Percentage of GoodwillPurchaseAccountingAdjustments-0.0100.0100.00.00.0-0.00.00.00.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.0190.0150.1630.063-0.139-0.4090.2611.509-1.32-0.1632.846-0.118-0.2730.477-0.082-2.198-3.191.687-0.816-5.4-155.451-6.996-3.368-213.334-255.665-326.457-0.126-0.1680.4483.3610.00.00.0
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:IncreaseDecreaseInOtherCurrentAssets

us-gaap:IncreaseDecreaseInOtherCurrentAssets


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value5.93146-30.33229-15.831-14.959-30.822370.502312832-6.566-22.506-10.06724-15.20731-0.899-1.731-2.17522-21.317-24.235-24.894205.581-17.0441522-5.923-2.64743-25.855-18.809-15.0441221-10.70522-38.49718390.349
Percentage of IncreaseDecreaseInOtherCurrentAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherCurrentLiabilities

us-gaap:IncreaseDecreaseInOtherCurrentLiabilities


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-8.628-13.977-38.6954749-23.259-2.183721-6.31-9.6862412-5.115-61.99973-5.208-1.179-12.827151913-0.4951012-16.119-56.28269-8.092-28.35510-4.39130-7.338-26.00712-11.811-33.7512.146415.985-15.7381245
Percentage of IncreaseDecreaseInOtherCurrentLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet

us-gaap:IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value7.1841.052-22.34-0.78411-0.32625-15.4610.8574911156.2645.3023.709106.621-2.1611.17510104.047-5.793-20.0656.0659.5372.278138.7024.9361923-3.5774.31852-9.613-1.721-8.34957-5.9392.541-20.51
Percentage of IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInReceivables

us-gaap:IncreaseDecreaseInReceivables


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value107-89.407-107.9375985-44.549-133.999671682.641-83.9834176-62.711-12.87377107-63.684-49.66730103-58.435-88.10750139-101.371-79.7626534-25.611-66.8134197-32.206-76.1887104-101.91788-75.088-33.00150-1.963-84.223-34.76561
Percentage of IncreaseDecreaseInReceivables100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestCostsIncurredCapitalized

us-gaap:InterestCostsIncurredCapitalized


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-31
Value0.4680.3480.60.70.6730.6270.80.80.6440.5560.50.80.6180.3820.290.2580.2220.1960.0720.2940.2880.262.3092.52.42.63.0082.93.32.42.5
Percentage of InterestCostsIncurredCapitalized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue


Life
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-30
Value3.80.1274.43.39.1-3.72.81.12.96.4-6.62.11.4-0.52.41.92.12.9-1.91.42.31.61.0-1.7
Percentage of LifeInsuranceCorporateOrBankOwnedChangeInValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value879528722018279338227-25.7212.0911831437010511912422831531416067181173-8.249421219174137313195961362511614912521515713312018016811885
Percentage of NetCashProvidedByUsedInOperatingActivitiesContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1

us-gaap:NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1


Noncash
Period End2020-12-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value-2500000.0005000000.000
Percentage of NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1100.00.00.0100.00.00.0

us-gaap:OperatingLeaseLeaseIncome

us-gaap:OperatingLeaseLeaseIncome


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value12121410111213111214
Percentage of OperatingLeaseLeaseIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-27000.0-9000.0-55000.0-22000.0-6000.0134000.08000.08000.091000.067000.089000.0-18000.0-9000.0-75000.0-42000.08000.07000.08000.0-80000.0-9000.06000.044000.0-32000.0-7000.0-15000.015000.0-30000.0-31000.040000.02000.0-5000.028000.0-98000.0-9000.0-23000.039000.0-5000.026000.0
Percentage of OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value-0.052-0.044-0.05-0.0130.1350.0120.0790.0390.055-0.051-0.043-0.105-0.069-0.019-0.024-0.027-0.117-0.042-0.030.008-0.065-0.035-0.043-0.021-0.065-0.0620.008-0.0360.003-0.01-0.142-0.044
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value-0.052-0.044-0.05-0.0130.1350.0120.0790.0394.496-0.051-0.102-0.107-1.896-0.004-0.039-0.018-1.588-0.0460.0010.033-0.15-0.108-0.034-0.133-12.578-0.208
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax100.0100.0100.0100.0100.0100.0100.0100.08174.5100.0237.2101.92747.821.1162.566.71357.3109.5-3.3412.5230.8308.679.1633.319350.8335.5

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value-25000.0-35000.0-18000.0-28000.0-7000.01000.0-4000.04000.0-12000.0-28000.0-34000.0-33000.0-34000.0-30000.0-27000.0-27000.0-31000.0-35000.0-37000.0-33000.0-36000.0-36000.0-33000.0-28000.0-28000.0-36000.0-35000.0-31000.0-32000.0-38000.08000.0-38000.0-44000.0-35000.0-33000.0-32000.0-38000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value-6000.0-9000.0-5000.0-7000.0-2000.0001000.0-3000.0-7000.0-9000.0-9000.0-10000.0-7000.0-15000.0-14000.0-17000.0-19000.0-20000.0-18000.0-19000.0-19000.0-17000.0-15000.0-15000.0-19000.0127000.0-16000.0-17000.0-20000.0122000.0-20000.0-23000.0-19000.0126000.0-17000.0-20000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value-112000.0-111000.0-112000.0-111000.0-112000.0-111000.0-111000.0-112000.0-111000.0-397000.0117000.0-92000.0-95000.0-92000.0-91000.0-92000.0-92000.0-91000.0-92000.0-92000.0-91000.0-92000.0-105000.0-100000.0-100000.0-99000.0-255000.0-82000.0-13000.0-344000.0511000.0510000.0396000.02772000.01725000.07782000.01834000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value-36000.0-37000.0-36000.0-37000.0-36000.0-36000.0-37000.0-36000.0-36000.0249000.0-265000.0-55000.0-53000.0-56000.0-56000.0-56000.0-56000.0-56000.0-56000.0-56000.0-56000.0-57000.0-52000.0-60000.0-60000.0-60000.0677000.0-50000.0-10000.0-204000.0-4794000.0297000.0322000.01626000.0-9267000.04570000.01077000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value457000.0466000.0509000.0471000.0480000.0462000.0608000.0292000.0276000.0310000.0864000.0442000.0449000.0418000.011000.0333000.0312000.0357000.03617000.0236000.0248000.0-1595000.0453000.0382000.0584000.0375000.015000.0261000.0245000.0275000.0657000.0271000.0424000.0648000.02079000.000
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value160000.0151000.0174000.0152000.0155000.0149000.0192000.095000.089000.0100000.0279000.0142000.0145000.0155000.036000.0203000.0190000.0217000.02101000.0143000.0150000.0-969000.0247000.0233000.0420000.0230000.015000.0159000.0150000.0168000.0249000.0166000.0543000.0319000.01379000.000
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312010-09-302010-06-30
Value-52000.0-44000.0-73000.0-50000.0-13000.0135000.04000.012000.079000.039000.055000.0-51000.0-43000.0-105000.0-69000.0-19000.0-24000.0-27000.0-117000.0-42000.0-30000.08000.0-65000.0-35000.0-43000.0-21000.0-65000.0-62000.08000.0-36000.03000.0-10000.0-142000.0-44000.0-56000.07000.0-43000.0-4000.0-21000.0087000.0000
Percentage of OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.00.00.0

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-312011-09-302011-06-302010-12-31
Value-13000.0-12000.0-19000.0-13000.0-4000.036000.003000.021000.010000.014000.0-13000.0-12000.0-28000.0-37000.0-10000.0-13000.0-15000.0-63000.0-23000.0-16000.05000.0-34000.0-19000.0-23000.0-11000.0-35000.0-33000.04000.0-19000.01000.0-5000.0-77000.0-24000.0-30000.04000.0-23000.0-12000.01000.047000.00
Percentage of OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:PaymentsForProceedsFromInvestments

us-gaap:PaymentsForProceedsFromInvestments


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-0.0043.2481.838-0.0010.045-0.0681.2940.0040.3730.340.7610.644-0.1581.0741.348-0.0980.2420.1161.452-0.318-0.2410.503-0.206-0.1011.241-2.4490.083-2.01.666-0.458-0.084-0.202-0.530.5141.463-0.016-11.1990.027200.187-19.8119.856-1.81-0.1222.632-1.404
Percentage of PaymentsForProceedsFromInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsOfStockIssuanceCosts us-gaap:StatementClassOfStock

us-gaap:PaymentsOfStockIssuanceCosts

mdu:Atthemarketoffering


Payments
Period End2021-06-30
Value400000.0
Percentage of PaymentsOfStockIssuanceCosts100.0

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302013-12-31
Value04127000.0000362000.00003015000.00002330000.0000757000.0007000.0316000.00000000
Percentage of PaymentsRelatedToTaxWithholdingForShareBasedCompensation0.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.0100.0100.00.00.00.00.00.00.00.0

us-gaap:PaymentsToAcquireBusinessesGross us-gaap:BusinessAcquisition

us-gaap:PaymentsToAcquireBusinessesGross

mdu:A2020AcquisitionMemberDomain


Payments
Period End2020-09-302020-06-302020-03-31
Value0.8-0.177
Percentage of PaymentsToAcquireBusinessesGross100.0100.0100.0

us-gaap:PaymentsToAcquireBusinessesNetOfCashAcquired

us-gaap:PaymentsToAcquireBusinessesNetOfCashAcquired


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value121.023340.753.136672.334220.0301397.849200.00.00.0
Percentage of PaymentsToAcquireBusinessesNetOfCashAcquired100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.00.00.00.0

us-gaap:ProceedsFromIssuanceOfCommonStock

us-gaap:ProceedsFromIssuanceOfCommonStock


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value3419-0.0250.00.03.411.2093630380.00.00.00.00.00.00.00.00.0047.3954.6359.8645.192127754140.00.00.00.00.00.00.0880.00.00.05.7442.2370.9960.5251.214
Percentage of ProceedsFromIssuanceOfCommonStock100.0100.0100.00.00.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.00.00.00.0100.00.00.00.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromIssuanceOfCommonStock us-gaap:StatementClassOfStock

mdu:Atthemarketoffering


Proceeds
Period End2021-06-302021-03-31
Value3419
Percentage of ProceedsFromIssuanceOfCommonStock99.9100.0

us-gaap:ProceedsFromSaleOfProductiveAssets

us-gaap:ProceedsFromSaleOfProductiveAssets


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value3.3679.035120.495184.541.421203.2594.938133.1653.325.9665.426
Percentage of ProceedsFromSaleOfProductiveAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromShortTermDebt

us-gaap:ProceedsFromShortTermDebt


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value0.0500.00.0750.00.05049700.00.00.00.016163.59.9160.00.00.00.04.5-24.6209.3172.90.00.00.0
Percentage of ProceedsFromShortTermDebt0.0100.00.00.0100.00.00.0100.0100.0100.00.00.00.00.0100.0100.0100.0100.0100.00.00.00.00.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:ProvisionForDoubtfulAccounts

us-gaap:ProvisionForDoubtfulAccounts


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value-0.841-0.3173.6111.0753.555
Percentage of ProvisionForDoubtfulAccounts100.0100.0100.0100.0100.0

us-gaap:ProvisionForDoubtfulAccounts us-gaap:StatementBusinessSegments

mdu:ConstructionMaterialsAndContracting


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.011-1.0490.728-0.3140.694
Percentage of ProvisionForDoubtfulAccounts-1.3330.920.2-29.219.5

mdu:ConstructionServices


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value-0.639-1.0791.6350.8961.15
Percentage of ProvisionForDoubtfulAccounts76.0340.445.383.332.3

mdu:Electric


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value-0.110.5380.4350.3030.555
Percentage of ProvisionForDoubtfulAccounts13.1-169.712.028.215.6

mdu:NaturalGasDistribution


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value-0.1031.2730.8110.191.156
Percentage of ProvisionForDoubtfulAccounts12.2-401.622.517.732.5

mdu:Pipeline


Provision
Period End2020-09-30
Value0.002
Percentage of ProvisionForDoubtfulAccounts0.1

us-gaap:PublicUtilitiesApprovedRateIncreaseDecreaseAmount dei:LegalEntity, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

us-gaap:PublicUtilitiesApprovedRateIncreaseDecreaseAmount

mdu:GreatPlainsNaturalGasCo., mdu:PendingRateCase, us-gaap:GasDistribution, mdu:MNPUC


Public
Period End2020-10-26
Value2.6
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount100.0

us-gaap:PublicUtilitiesApprovedRateIncreaseDecreaseAmount dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency

mdu:MontanaDakotaUtilitiesCo., us-gaap:GasDistribution, mdu:NDPSC


Public
Period End2021-06-01
Value13
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount0.0

us-gaap:PublicUtilitiesApprovedRateIncreaseDecreaseAmount dei:LegalEntity, us-gaap:PublicUtility, us-gaap:RegulatoryAgency, us-gaap:SubsequentEventType

mdu:CascadeNaturalGas, mdu:PipelineCostRecoveryMechanism, mdu:WUTC, us-gaap:SubsequentEvent


Public
Period End2020-11-012019-11-01
Value1.10.44
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount0.00.0

mdu:CascadeNaturalGas, us-gaap:GasDistribution, mdu:WUTC, us-gaap:SubsequentEvent


Public
Period End2021-07-012020-03-01
Value-0.3916.5
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount0.00.0

mdu:MontanaDakotaUtilitiesCo., mdu:Electric, mdu:NDPSC, us-gaap:SubsequentEvent


Public
Period End2020-11-01
Value6.3
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount0.0

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:Mtpsc, us-gaap:SubsequentEvent


Public
Period End2020-09-01
Value0.3
Percentage of PublicUtilitiesApprovedRateIncreaseDecreaseAmount0.0

mdu:MontanaDakotaUtilitiesCo., us-gaap:Electricity, mdu:NDPSC, us-gaap:SubsequentEvent