FIBK


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

Table of contents


us-gaap:StatementClassOfStock
us-gaap:CommonStockSharesAuthorized

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:TierOneRiskBasedCapitalToRiskWeightedAssets
dei:LegalEntity

us-gaap:CapitalToRiskWeightedAssets
dei:LegalEntity

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxesPaid

us-gaap:InterestAndFeeIncomeLoansAndLeases

us-gaap:InterestExpense

us-gaap:InterestIncomeExpenseNet

us-gaap:InterestPaidNet

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:ProductOrService
us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax

us-gaap:Assets
us-gaap:ConsolidatedEntities

us-gaap:Liabilities
us-gaap:ConsolidatedEntities

us-gaap:LiabilitiesAndStockholdersEquity
us-gaap:ConsolidatedEntities

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

us-gaap:TierOneRiskBasedCapital
dei:LegalEntity

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
us-gaap:ConsolidatedEntities

us-gaap:PropertyPlantAndEquipmentGross
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AmortizationOfIntangibleAssets

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:Goodwill

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsNet

us-gaap:OtherAssets
us-gaap:ConsolidatedEntities

us-gaap:LongTermDebt
us-gaap:ConsolidatedEntities
us-gaap:ConsolidatedEntities, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:LongTermDebtAndCapitalLeaseObligations

us-gaap:DeferredIncomeTaxLiabilitiesNet

us-gaap:TimeDepositsNoncurrent

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

us-gaap:CommonStocksIncludingAdditionalPaidInCapital

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DepreciationDepletionAndAmortization

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents

us-gaap:ShareBasedCompensation

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:PaymentsOfDividendsCommonStock

us-gaap:PaymentsForRepurchaseOfCommonStock
us-gaap:ConsolidatedEntities, us-gaap:Range, us-gaap:DebtInstrument
us-gaap:DebtInstrumentInterestRateStatedPercentage

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice

us-gaap:DeferredTaxLiabilities

fibk:CapitalizationOfInternallyOriginatedMortgageServicingRightsNoncashSupplementalDisclosures
us-gaap:HedgingDesignation
fibk:FeeIncomeonDerivatives

fibk:ImpairmentofRealEstateandOtherAssetsPendingDisposal

fibk:OtherRealEstateOwnedExpenseNetOfIncome

fibk:PaymentsForProceedsFromRecoveriesofLoansPreviouslyChargedoff

fibk:RealEstateAcquiredThroughForeclosureAdditions

fibk:RealEstateAcquiredThroughForeclosureDisposals

fibk:RealEstateAcquiredThroughForeclosureValuationAdjustments

fibk:SharesRepurchasedDuringThePeriodAsPercentageOfSharesAuthorizedForRepurchasePercent

us-gaap:AcceleratedShareRepurchasesAdjustmentToRecordedAmount

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments

us-gaap:AllowanceForLoanAndLeaseLossesWriteOffs
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancialInstrument
us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss

us-gaap:DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense
us-gaap:FinancialInstrument
us-gaap:FinancialInstrument
us-gaap:DebtSecuritiesUnrealizedGainLoss

us-gaap:DefinedBenefitPlanActuarialGainLoss
us-gaap:HedgingDesignation
us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet

us-gaap:DividendsCommonStockCash
us-gaap:StatementEquityComponents

us-gaap:EquipmentExpense

us-gaap:FederalDepositInsuranceCorporationPremiumExpense

us-gaap:FeesAndCommissionsMortgageBankingAndServicing

us-gaap:FinanceLeaseRightOfUseAssetAmortization

us-gaap:FinancingReceivableAccruedInterestWriteoff

us-gaap:FinancingReceivableAllowanceForCreditLossesEffectOfChangeInMethod

us-gaap:FinancingReceivableAllowanceForCreditLossesRecovery
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:HedgingDesignation
us-gaap:GainLossOnFairValueHedgesRecognizedInEarnings

us-gaap:GainLossOnSaleOfDebtInvestments

us-gaap:GainLossOnSaleOfInvestments

us-gaap:GainLossOnSaleOfLoansAndLeases

us-gaap:GainLossOnSaleOfPropertyPlantEquipment

us-gaap:GainsLossesOnSalesOfOtherRealEstate

us-gaap:HeldToMaturitySecuritiesTransferredSecurityUnrealizedGainLoss

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities

us-gaap:IncreaseDecreaseInAccruedInterestReceivableNet

us-gaap:IncreaseDecreaseInDeposits

us-gaap:IncreaseDecreaseInInterestPayableNet

us-gaap:IncreaseDecreaseInOtherOperatingAssets

us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:InformationTechnologyAndDataProcessing

us-gaap:InterestAndDividendIncomeOperating

us-gaap:InterestExpenseDeposits

us-gaap:InterestExpenseJuniorSubordinatedDebentures

us-gaap:InterestExpenseOtherLongTermDebt

us-gaap:InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase

us-gaap:InterestIncomeDomesticDeposits

us-gaap:InterestIncomeExpenseAfterProvisionForLoanLoss

us-gaap:InterestIncomeSecuritiesTaxExempt

us-gaap:InterestIncomeSecuritiesTaxable
us-gaap:ProductOrService
us-gaap:InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions

us-gaap:LaborAndRelatedExpense

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue

us-gaap:MortgageServicingRightsMSRImpairmentRecovery

us-gaap:NoninterestExpense

us-gaap:NoninterestIncome

us-gaap:NoninterestIncomeOtherOperatingIncome

us-gaap:OccupancyNet

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossAfterTax

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossTax

us-gaap:OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal
us-gaap:CumulativeEffectPeriodOfAdoption

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax

us-gaap:OtherComprehensiveIncomeLossTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax
us-gaap:HedgingDesignation

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax

us-gaap:OtherLaborRelatedExpenses

us-gaap:OtherNoninterestExpense

us-gaap:PaymentsForOriginationOfMortgageLoansHeldForSale

us-gaap:PaymentsForProceedsFromOtherLoansAndLeases

us-gaap:PaymentsForProceedsFromProductiveAssets

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt

us-gaap:PaymentsToAcquireHeldToMaturitySecurities

us-gaap:ProceedsFromIssuanceOfCommonStock

us-gaap:ProceedsFromIssuanceOfUnsecuredDebt

us-gaap:ProceedsFromLifeInsurancePolicies

us-gaap:ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase

us-gaap:ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities

us-gaap:ProceedsFromSaleAndMaturityOfHeldToMaturitySecurities

us-gaap:ProceedsFromSaleOfMortgageLoansHeldForSale

us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans

us-gaap:ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets

us-gaap:ProfessionalFees

us-gaap:ProvisionForLoanAndLeaseLosses
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax

us-gaap:RepaymentsOfOtherLongTermDebt

us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised
us-gaap:StatementEquityComponents
us-gaap:StatementClassOfStock
us-gaap:StockRepurchasedAndRetiredDuringPeriodShares

us-gaap:StockRepurchasedAndRetiredDuringPeriodValue
us-gaap:StatementEquityComponents

us-gaap:TransferToOtherRealEstate

us-gaap:TreasuryStockAcquiredAverageCostPerShare

us-gaap:UnrealizedGainLossOnDerivatives
us-gaap:StatementClassOfStock
dei:EntityCommonStockSharesOutstanding
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
fibk:AccruedInterestPayableFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
fibk:AccruedInterestReceivableFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:ConsolidatedEntities
fibk:AdvancestoSubsidiariesNet

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn
dei:LegalEntity

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule
dei:LegalEntity

fibk:CommonEquityTierOneCapitalToBeWellCapitalized
dei:LegalEntity

fibk:CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets
dei:LegalEntity

fibk:CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets
dei:LegalEntity

fibk:CommonEquityTierOneRiskedBasedCapital
dei:LegalEntity

fibk:ContractualMaturitiesTimeDeposits100000OrMoreAfter4Years

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter2years

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter3years

fibk:ContractualMaturitiesTimeDepositsSixMonthsthroughTwelveMonths

fibk:ContractualMaturitiesTimeDepositsThreeMonthsorLess

fibk:ContractualMaturitiesTimeDepositsThreeMonthsthroughSixMonths

fibk:CreditExtensionCommitments
us-gaap:GuaranteeObligationsByNature
us-gaap:GuaranteeObligationsByNature
fibk:CreditExtensionCommitmentsBeyondOneYear

fibk:DeferredTaxAssetsNonPerformingLoanInterest

fibk:DeferredTaxAssetsRightofUseAsset

fibk:DeferredTaxLiabilitiesAgencyStockDividends

fibk:DeferredTaxLiabilitiesDeferredLoanCosts

fibk:DeferredTaxLiabilityLeaseLiabilities

fibk:Deferredtaxassetloandiscount
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
fibk:DepositsExcludingTimeDepositsFairValueDisclosure
us-gaap:FairValueByMeasurementBasis

fibk:FDICDepositInsuranceLimit

fibk:FederalReserveBankUnrestrictedCashHeldCarryingValue

fibk:FinancingReceivableCARESAct

fibk:FinancingReceivableModificationsRecordedInvestmentAccrualMethod

fibk:FinancingReceivableModificationsRecordedInvestmentNonAccrual

fibk:ForeclosedResidentialRealEstateincludedinOtherRealEstateOwned
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
fibk:ImpairedFinancingReceivableRelatedAllowancePartialLoanChargeOffs
us-gaap:InvestmentType
fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis
us-gaap:InvestmentType
fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveFairValue
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency
fibk:LoansReceivableImpairedFairValueDisclosure
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
us-gaap:FairValueByMeasurementFrequency
us-gaap:DisposalGroupClassification, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency
fibk:LongLivedAssetsToBeDisposedFairValueDisclosure
us-gaap:DisposalGroupClassification, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementFrequency
us-gaap:ConsolidatedEntities, us-gaap:LongtermDebtType
fibk:LongTermDebtAcquiredorAssumed
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
fibk:OtherLongTermDebtFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:LeaseArrangementType
fibk:OwnershipPercentageInPartnership

fibk:PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtCost
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
fibk:RealEstateAcquiredThroughForeclosureFairValueDisclosure
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
us-gaap:FinancialInstrument
fibk:ServicingAssetAsPercentageOfServicedLoansHeldInPortfolio
us-gaap:FinancialInstrument
fibk:ServicingAssetAtAmortizedCostBeforeValuationReserve

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn
dei:LegalEntity

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn
dei:LegalEntity

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:TimeDeposits250000orMore
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
fibk:TimeDepositsFairValueDisclosure
us-gaap:FairValueByMeasurementBasis

fibk:TimeDepositsObtainedCertificateOfDepositAccountRegistryService

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent

us-gaap:AccruedInvestmentIncomeReceivable

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax
us-gaap:StatementEquityComponents

us-gaap:AllowanceForDoubtfulAccountsReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InitialApplicationPeriodCumulativeEffectTransition

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent

us-gaap:AllowanceForNotesAndLoansReceivableNoncurrent
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:AssetsFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency
us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure
us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis
us-gaap:FinancialInstrument
us-gaap:FinancialInstrument
us-gaap:AvailableForSaleSecuritiesAmortizedCost
us-gaap:StatementGeographical, us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue

us-gaap:AvailableForSaleSecuritiesDebtSecurities
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument
us-gaap:FinancialInstrument

us-gaap:Capital
dei:LegalEntity
us-gaap:ConsolidatedEntities, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:CapitalLeaseObligations

us-gaap:CapitalRequiredForCapitalAdequacy
dei:LegalEntity

us-gaap:CapitalRequiredToBeWellCapitalized
dei:LegalEntity

us-gaap:CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
dei:LegalEntity
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:CashAndCashEquivalentsFairValueDisclosure
us-gaap:FairValueByMeasurementBasis

us-gaap:CashAndDueFromBanks

us-gaap:CashCashEquivalentsAndFederalFundsSold
us-gaap:ConsolidatedEntities
dei:LegalEntity, us-gaap:ProductOrService
us-gaap:CashSurrenderValueOfLifeInsurance
us-gaap:ProductOrService

us-gaap:ContractualMaturitiesTimeDeposits100000OrMoreAfter12Months

us-gaap:ContractualMaturitiesTimeDeposits100000OrMoreSixMonthsThrough12Months

us-gaap:ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsOrLess

us-gaap:ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsThroughSixMonths

us-gaap:DebtInstrumentInterestRateEffectivePercentage
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:SubordinatedBorrowing

us-gaap:DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet

us-gaap:DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleUnrealizedLossPosition
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DeferredCompensationLiabilityCurrentAndNoncurrent
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:DeferredCompensationPlanAssets
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsOperatingLossCarryforwards

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

us-gaap:DeferredTaxLiabilitiesGoodwillAndIntangibleAssets

us-gaap:DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates

us-gaap:DeferredTaxLiabilitiesMortgageServicingRights

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DeferredTaxLiabilitiesPrepaidExpenses

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment

us-gaap:DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan

us-gaap:DemandDepositAccounts

us-gaap:Deposits

us-gaap:DepositsSavingsDeposits

us-gaap:DerivativeAssetNotionalAmount
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:DerivativeAssets
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis

us-gaap:DerivativeAssetsLiabilitiesAtFairValueNet

us-gaap:DerivativeCollateralObligationToReturnCash
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeCollateralObligationToReturnSecurities
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeCollateralRightToReclaimSecurities
us-gaap:Collateral
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFairValueOfDerivativeAsset
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFairValueOfDerivativeLiability
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral
us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFairValueOfDerivativeNet
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:DerivativeInstrumentsAndHedges

us-gaap:DerivativeLiabilities
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis

us-gaap:DerivativeLiabilityNotionalAmount
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoaned

us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedAmountOffsetAgainstCollateral

us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedCollateralRightToReclaimCash

us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedCollateralRightToReclaimSecurities

us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedGross
us-gaap:CreditDerivativesByContractType
us-gaap:DerivativeNotionalAmount
us-gaap:AwardType
us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
us-gaap:ConsolidatedEntities
us-gaap:EquityMethodInvestments
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations
us-gaap:FairValueByMeasurementBasis

us-gaap:FederalFundsSold
us-gaap:ConsolidatedEntities, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable

us-gaap:FederalHomeLoanBankStock

us-gaap:FederalReserveBankStock
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FinancialInstrumentsSoldNotYetPurchasedAtFairValue
us-gaap:FairValueByMeasurementBasis
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableLoanInProcess
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:FinancingReceivablesPeriodPastDue

us-gaap:FinancingReceivableModificationsRecordedInvestment
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType, us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedInCurrentFiscalYear
us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentCurrent
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentNonaccrualStatus
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentPastDue
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:FinancingReceivablesPeriodPastDue
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRevolving
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAccumulatedAmortization
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:GuaranteeObligationsCurrentCarryingValue

us-gaap:HedgedAssetFairValueHedgeCumulativeIncreaseDecrease

us-gaap:HeldToMaturitySecurities
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
us-gaap:FinancialInstrument

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue

us-gaap:HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount

us-gaap:HeldToMaturitySecuritiesFairValue
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis
us-gaap:FinancialInstrument

us-gaap:ImpairedFinancingReceivableRecordedInvestment
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:ImpairedFinancingReceivableRelatedAllowance

us-gaap:ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance

us-gaap:IncomeTaxesReceivable

us-gaap:InterestBearingDepositLiabilities

us-gaap:InterestBearingDepositsInBanks

us-gaap:InterestPayableCurrentAndNoncurrent

us-gaap:InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet

us-gaap:InterestRateDerivativeAssetsAtFairValue
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue

us-gaap:InterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue

us-gaap:InterestRateDerivativeLiabilitiesAtFairValue
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:InterestReceivable
us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType

us-gaap:JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
us-gaap:ConsolidatedEntities
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:SubordinatedBorrowing
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:LiabilitiesFairValueDisclosure
us-gaap:FairValueByMeasurementBasis

us-gaap:LifeInsuranceCorporateOrBankOwnedAmount
us-gaap:LongtermDebtType
us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity

us-gaap:LoansAndLeasesReceivableAllowance

us-gaap:LoansAndLeasesReceivableCollateralForSecuredBorrowings
us-gaap:Collateral
us-gaap:Collateral, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

us-gaap:LoansAndLeasesReceivableDeferredIncome

us-gaap:LoansAndLeasesReceivableGrossCarryingAmount
us-gaap:FinancialInstrumentPerformanceStatus, us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable
us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InternalCreditAssessment

us-gaap:LoansAndLeasesReceivableNetOfDeferredIncome

us-gaap:LoansAndLeasesReceivableNetReportedAmount
us-gaap:RelatedPartyTransactionsByRelatedParty
us-gaap:LoansAndLeasesReceivableRelatedParties
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:LoansHeldForSaleFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:LoansReceivableFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:LoansReceivableHeldForSaleAmount
us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:LoansReceivableHeldForSaleNetNotPartOfDisposalGroup

us-gaap:LongTermAccountsNotesAndLoansReceivableNetNoncurrent

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo

us-gaap:MarketableSecurities
us-gaap:Ownership
us-gaap:MinorityInterestOwnershipPercentageByParent

us-gaap:MortgageLoansInProcessOfForeclosureAmount

us-gaap:MortgagesHeldForSaleFairValueDisclosure

us-gaap:MunicipalDebtSecuritiesAtCarryingValue
us-gaap:FinancialInstrument

us-gaap:NoninterestBearingDepositLiabilities

us-gaap:OffBalanceSheetCreditLossLiability
us-gaap:CumulativeEffectPeriodOfAdoption
us-gaap:InitialApplicationPeriodCumulativeEffectTransition

us-gaap:OperatingLeasesFutureMinimumPaymentsDue
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueCurrent
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInFiveYears
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInFourYears
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInThreeYears
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInTwoYears
us-gaap:LeaseArrangementType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueThereafter
us-gaap:LeaseArrangementType
us-gaap:ConsolidatedEntities
us-gaap:OtherLiabilities

us-gaap:OtherLongTermDebt

us-gaap:PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue
us-gaap:FinancialInstrument
us-gaap:PrincipalAmountOutstandingOfLoansHeldInPortfolio

us-gaap:RealEstateAcquiredThroughForeclosure

us-gaap:SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure

us-gaap:SecuritiesSoldUnderAgreementsToRepurchase

us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimCash

us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral

us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseGross

us-gaap:ServicingAssetAtAmortizedValue
us-gaap:FinancialInstrument
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:ServicingAssetAtFairValueAmount
us-gaap:FairValueByMeasurementBasis
us-gaap:FinancialInstrument
us-gaap:Range, us-gaap:DisposalGroupClassification, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:MeasurementInputType, us-gaap:ValuationTechnique
us-gaap:ServicingAssetMeasurementInput
us-gaap:Range, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument, us-gaap:MeasurementInputType, us-gaap:ValuationTechnique
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
us-gaap:PlanName
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
us-gaap:TitleOfIndividual, us-gaap:StatementClassOfStock

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:ScheduleOfSharesSubjectToMandatoryRedemptionBySettlementTerms
us-gaap:SharesSubjectToMandatoryRedemptionSettlementTermsAmount

us-gaap:StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
us-gaap:StatementClassOfStock
us-gaap:StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased

us-gaap:TaxCreditCarryforwardAmount

us-gaap:TierOneLeverageCapital
dei:LegalEntity

us-gaap:TierOneLeverageCapitalRequiredForCapitalAdequacy
dei:LegalEntity

us-gaap:TierOneLeverageCapitalRequiredToBeWellCapitalized
dei:LegalEntity

us-gaap:TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
dei:LegalEntity

us-gaap:TierOneLeverageCapitalToAverageAssets
dei:LegalEntity

us-gaap:TierOneRiskBasedCapitalRequiredForCapitalAdequacy
dei:LegalEntity

us-gaap:TierOneRiskBasedCapitalRequiredToBeWellCapitalized
dei:LegalEntity

us-gaap:TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
dei:LegalEntity

us-gaap:TimeDepositMaturitiesAfterYearFive

us-gaap:TimeDepositMaturitiesYearThree

us-gaap:TimeDepositMaturitiesYearTwo

us-gaap:TimeDeposits

us-gaap:TimeDeposits100000OrMore

us-gaap:TimeDepositsLessThan100000
us-gaap:UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchased
us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
us-gaap:FinancialInstrument
us-gaap:ValuationAllowanceForImpairmentOfRecognizedServicingAssetsBalance

Plots across concepts


IncomeStatement
Other Comprehensive Income Loss Net Of Tax
Expenses
Interest Expense
Balance Sheet
Long Term Debt
Assets
Derivative Assets
Current Assets
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents
NonCurrent Assets
Property Plant And Equipment Net
PropertyPlantAndEquipmentNet
Accumulated Depreciation Depletion And Amortization Property Plant And Equipment
Liabilities
Derivative Liabilities
Noncurrent Liabilities
Deferred Income Tax Liabilities Net
Stockholders Equity
Accumulated Other Comprehensive Income Loss Net Of Tax
CashFlow
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInOperatingActivities
Gain Loss On Sale Of Property Plant Equipment
NetCashProvidedByUsedInFinancingActivities
Payments For Repurchase Of Common Stock
Shares
Weighted Average Number Of Shares Outstanding Basic
DividendsAndRepurchase
Payments For Repurchase Of Common Stock
BanksAndOrInsurance
Interest And Dividend Income Operating
AssetsBanks
Cash And Due From Banks
LiabilitiesBanks
Accounts Payable And Accrued Liabilities Current And Noncurrent

Tables

  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
 us-gaap:CommonStockSharesAuthorized us-gaap:StatementClassOfStock us-gaap:CommonClassANANA100.0NANANA100.0NANANA100.0NANANA100.0NANANA100.0NANANA100.0NANANA100.0NANANA100.0NANANANANANANANANANANANANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding █▁61.72782161.714063NA63.86145764.08248964.937107NA65.04348664.70745960.59807NA58.64047556.69902156.652NA56.53086848.07445145.238908NA44.80592144.64517545.114052NA45.57897845.60668645.840191NA45.46028844.57596344.620776NA44.28484443.90828743.428382NA43.12007743.06020442.982543NA42.84166342.896611NANANANA
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic █▁61.65759361.591877NA63.76447464.00445564.790186NA64.83232464.50454660.311171NA58.25457556.33518656.241201NA56.09440147.61297144.680258NA44.41521344.26898544.719218NA45.15010445.14312245.37823NA44.91185844.0442643.997815NA43.69956643.48050243.140409NA42.98956442.96692642.873769NA42.77425942.781894NANANANA
 us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities us-gaap:PerformanceSharesNA0.368793NANANA0.30941NANANA0.154387NANANA0.164019NANANA0.18768NANANA0.226821NANANA0.16677NANANANANANANANANANANANANANANANANANANA
 us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities us-gaap:RestrictedStock▁█0.0841650.092602NA0.0683970.1083690.113468NA0.0048080.0007610.121452NA0.0043768.5e-050.139943NA0.00.0962620.096897NA0.0001350.0967260.040865NA0.005884NA0.16677NANANA0.111417NANANA0.06176NANANA0.048196NANANANANANANA
us-gaap:EarningsPerShareBasic ▇█▇▇▅▄█▇▆▇▆▇▇▆▆▅▄▅▅▅▅▄▅▄▅▄▅▄▄▅▄▅▅▄▃▃▂▂▃▂▂▂▂▁▁0.690.830.74999999999999980.760.570.450.810.760.590.690.66999999999999990.710.740.650.60999999999999990.490.460.520.55999999999999980.570.580.450.520.450.490.460.50.430.480.490.480.540.490.460.380.360.280.260.28999999999999990.260.210.20.240.180.14
us-gaap:EarningsPerShareDiluted ▇█▇▇▅▄█▇▆▇▆▇▇▆▆▄▄▅▅▅▅▄▅▄▅▄▅▄▄▄▄▅▅▄▃▃▂▂▃▂▂▂▂▁▁0.690.830.74999999999999980.760.570.450.80000000000000030.760.590.690.66000000000000010.710.740.650.59999999999999990.480.450.510.54999999999999980.560.570.450.510.440.490.460.50.420.470.480.470.540.490.460.370.350.280.260.28999999999999990.260.210.20.240.180.14
us-gaap:TierOneRiskBasedCapitalToRiskWeightedAssets ████▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁1.217e-051.228e-051.233e-051.256e-051.285e-071.28e-071.341e-071.3009999999999998e-071.273e-071.25e-071.226e-071.20113171339635e-071.21468321953691e-071.20658308332613e-071.1930000000000002e-071.19e-071.1690000000000001e-071.375e-071.389e-071.36e-071.3700000000000002e-071.3700000000000002e-071.4e-071.3800000000000002e-071.3900000000000001e-071.3900000000000001e-071.45e-071.4699999999999998e-071.5e-071.5199999999999998e-071.49e-071.48e-071.45e-071.4099999999999998e-071.36e-071.45e-071.4199999999999997e-07NA1.4599999999999998e-07NANANANANANA
us-gaap:CapitalToRiskWeightedAssets ████▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁1.389e-051.404e-051.419e-051.4449999999999999e-051.476e-071.367e-071.4099999999999998e-071.371e-071.343e-071.3230000000000001e-071.299e-071.27597797584208e-071.2974881784239002e-071.2904123824445298e-071.276e-071.276e-071.2559999999999999e-071.494e-071.5129999999999999e-071.49e-071.5e-071.5e-071.54e-071.53e-071.54e-071.54e-071.62e-071.6300000000000002e-071.67e-071.6800000000000002e-071.6800000000000002e-071.67e-071.6300000000000002e-071.59e-071.56e-071.65e-071.62e-07NA1.65e-07NANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:ComprehensiveIncomeNetOfTax █▁▆▆██▇▇▇█▇▅▆▃▄▄▄▄▂▄▅▄▃▄▃▄▄▃▄▅▃▄▁▃▃▃▃▃▂▃▄▂▁▂59.91.541.645.062.158.150.052.052.861.855.237.039.119.521.28226.28626.45728.6617.81523.59331.37524.31918.39626.74816.89827.69327.87217.16522.79630.07512.68224.902-0.07416.59314.02516.70111.7812.6748.21713.60622.6029.779-2.7359.791NA
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest ▆█▇▇▅▄█▇▅▆▆▆▆▅▅▄▃▃▄▄▄▃▄▃▃▃▄▃▃▃▃▄▃▃▂▂▂▁▂▁▁55.165.561.763.047.137.568.964.448.853.052.253.553.647.049.4340.96633.74932.57737.75537.97639.19730.33135.08530.21233.7431.4235.10629.22632.37932.90431.86336.98432.94430.91125.77624.62319.53718.32620.0617.57614.526NANANANA
us-gaap:IncomeTaxExpenseBenefit ▆▇▇▇▅▄█▇▅▅▆▆▆▅▇▇▆▄▆▆▇▅▆▅▅▅▆▅▅▅▅▆▅▅▄▄▃▃▃▃▂▂▂▂▁12.614.114.80000000000000414.710.48.216.515.310.911.411.812.111.910.315.16113.70711.8819.45112.9912.78313.64310.20711.65410.0511.51810.4412.3310.07111.30211.51111.08813.17211.43910.8678.9318.4686.5276.1126.7955.6554.6724.4935.23.862.628
us-gaap:IncomeTaxesPaid ▆▇▆▅▅▅▆▅▇▃▅▄▄▄▄▅▁█▆▅▇▄▃▅▆▄▄▄▆▃▅▅▆▄▄▃▅▃▄▄▅▃▇▄14.721.018.411.513.011.516.410.324.50.09.56.15.14.64.489.9-14.37128.7514.00312.8523.364.2060.08.88513.355.15.554.9116.190.09.359.69117.4623.3764.80.012.640.14.223.698.730.022.0253.67NA
us-gaap:InterestAndFeeIncomeLoansAndLeases ▆▇█▇▇▇███▇▇▆▅▅▅▅▃▂▃▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▂▂▂▂▂▂▂105.4107.8117.0112.3112.1112.0118.6120.0120.9111.4112.2103.996.591.793.12694.01973.89563.72968.14365.62662.63462.81664.1862.06260.40259.37161.17961.00755.56553.71855.4454.90154.85355.49357.4757.41858.08457.9160.52961.37261.47562.39165.04467.03367.501
us-gaap:InterestExpense ▁▁▂▂▂▄▅▇█▇▆▅▄▃▃▃▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▂▃▃▃▄▄▅▅▆▇█4.54.65.35.96.39.111.815.816.814.612.711.29.27.87.857.9746.5465.5644.5514.3544.3264.434.7134.454.434.4674.9514.6464.4584.5514.7364.9735.1965.796.6287.177.8938.4238.9719.99111.02412.04513.36515.22116.691
us-gaap:InterestIncomeExpenseNet ▇▇█▇▇▇███▇▇▆▆▅▅▅▃▂▃▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▂▁▁▁▂▂118.8120.7128.4123.0122.5123.1128.2125.5125.3116.0118.9110.0103.899.8100.836100.79179.32368.89373.60170.58167.63367.9568.4266.3365.28864.32565.51665.08259.72758.13659.97458.95658.7659.27760.97361.00561.17460.63463.03563.49262.52761.79862.8563.74463.176
us-gaap:InterestPaidNet ▃▁▃▃▃▅▆█▇▆▆▅6.33.57.56.77.810.912.015.914.412.411.610.7NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:NetIncomeLoss ▆█▇▇▆▄█▇▆▆▆▆▆▆▅▄▃▄▄▄▄▃▄▃▃▃▃▃▃▃▃▄▃▃▃▂▂▂▂▂▁▁▂▁▁42.551.446.948.336.729.352.449.137.941.640.441.441.736.734.26827.25921.86823.12624.76525.19325.55420.12423.43120.16222.22220.9822.77619.15521.07721.39320.77523.81221.50520.04416.84516.15513.0112.21413.26511.9219.8549.50610.8388.7296.659
us-gaap:OtherComprehensiveIncomeLossNetOfTax █▁17.4-49.9NA-3.325.428.8-2.42.914.920.214.8-4.4-2.6-17.2NA-0.9734.5895.535-16.95-1.65.8214.195-5.0356.586-5.3246.7135.096-1.991.7198.682-8.0931.09-21.579-3.451-2.820.546-1.230.46-5.0481.68512.748NANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService us-gaap:CreditAndDebitCard▅▃▄▃▁▃▄▄▃▁▂▃█▃▇▇▃11.410.211.110.59.310.210.810.810.59.49.810.112.910.512.312.410.2NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService us-gaap:DepositAccount▂▂▃▃▁▆▆▆▆▅▆▇▆▇██▅3.93.84.34.33.65.45.45.35.45.05.25.75.35.66.05.95.1NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService us-gaap:FinancialServiceOther▁▂▂█▄▇▇▆▆▇▆▅▆▆▅▅▅1.62.12.15.02.94.74.44.24.24.34.03.43.83.93.73.63.4NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:Assets ██▇▇▇▅▅▅▅▅▅▅▄▄▄▄▄▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁18940.518443.417648.717069.516471.414411.414644.214701.614414.613498.213300.213355.812235.712273.412213.25512206.47312236.3429061.2349063.8958973.8478605.3768690.688728.1968604.538386.2188528.5428609.9368481.3527651.3797617.8257564.6517500.17291.5087439.3177721.7617461.1527305.1767394.3067325.5277307.1547202.791NA7500.97NANA
us-gaap:Liabilities ██▇▇▆▅▅▅▅▅▄▄▄▄▄▄▄▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁16969.616510.015688.915091.914472.512455.312630.312719.012466.011761.311606.311701.410777.410841.010785.63910787.06310830.9648059.6388081.3027991.3437640.2517748.6667777.7037665.9557461.3637614.0927701.0127595.4886812.8536792.1876763.076707.246521.5546667.9446970.5756663.2826518.8416615.0316554.5076539.1996443.446NA6764.168NANA
us-gaap:LiabilitiesAndStockholdersEquity ██▇▇▇▅▅▅▅▅▅▅▄▄▄▄▄▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁18940.518443.417648.717069.516471.414411.414644.214701.614414.613498.213300.213355.812235.712273.412213.25512206.47312236.3429061.2349063.8958973.8478605.3768690.688728.1968604.538386.2188528.5428609.9368481.3527651.3797617.8257564.6517500.17291.5087439.3177721.7617461.1527305.1767394.3067325.5277307.1547202.791NA7500.97NANA
us-gaap:StockholdersEquity █████████▆▆▆▅▅▅▅▅▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁1970.91933.41959.81977.61998.91956.12013.91982.61948.61736.91693.91654.41458.31432.41427.6161419.411405.3781001.596982.593982.504965.125942.014950.493938.575924.855914.45908.924885.864838.526825.638801.581792.86769.954771.373751.186797.87786.335779.275771.02767.955759.345741.697736.802744.703740.188
us-gaap:TierOneRiskBasedCapital ████████▇▆▆▆▅▅▅▄▄▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▁▁▁▁▁1415.61396.41369.01378.31393.11367.71422.31385.21346.31237.91212.01181.21086.81058.01040.31026.0161011.141880.777894.273877.285867.179848.709861.339843.096835.198738.388807.229808.289765.715753.154739.246722.201699.166677.787652.929695.572683.363NA704.229NANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents ▇██▆▄▂▃▃▃▂▁▂▁1948.42196.02276.81860.61425.0869.21076.81269.61128.9955.2822.0965.0712.0NA758.9NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:PropertyPlantAndEquipmentGross NANA491.3NANANA475.1NANANA422.0NANANA404.2NANANA346.648NANANA332.674NANANA324.907NANANA303.401NANANA303.154NANANA291.191NANANANANANA
 us-gaap:PropertyPlantAndEquipmentGross us-gaap:PropertyPlantAndEquipmentByType us-gaap:BuildingAndBuildingImprovementsNANA349.5NANANA330.1NANANA268.1NANANA257.1NANANA218.317NANANA213.321NANANA209.328NANANA196.95NANANA195.549NANANA188.509NANANANANANA
 us-gaap:PropertyPlantAndEquipmentGross us-gaap:PropertyPlantAndEquipmentByType us-gaap:FurnitureAndFixturesNANA88.9NANANA94.2NANANA104.0NANANA97.7NANANA88.537NANANA81.354NANANA74.959NANANA68.87NANANA68.688NANANA63.939NANANANANANA
 us-gaap:PropertyPlantAndEquipmentGross us-gaap:PropertyPlantAndEquipmentByType us-gaap:LandNANA52.9NANANA50.8NANANA49.9NANANA49.4NANANA39.794NANANA37.999NANANA40.62NANANA37.581NANANA38.917NANANA38.743NANANANANANA
us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment NANA179.0NANANA169.1NANANA176.8NANANA162.3NANANA152.191NANANA141.862NANANA129.695NANANA123.711NANANA115.589NANANA106.42NANANANANANA
us-gaap:AmortizationOfIntangibleAssets ▇▇▇▇▇████▆▆▅▅▅▅▅▃▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁2.52.52.5999999999999992.72.72.92.93.03.02.32.42.01.71.81.8611.8851.0620.630.8980.8750.8270.8270.8370.8420.8540.8550.8550.6880.3540.3540.3540.3550.3550.3540.3540.3550.3550.3550.3610.3620.3610.362NANANA
us-gaap:PropertyPlantAndEquipmentNet ▇▇█▇▇▇▇▇█▇▄▄▄▄▄▄▄▂▂▂▁▁▂▂▁▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁299.1305.5312.3307.8309.5308.5306.0302.8321.1298.2245.2244.2233.7240.2241.9242.94243.152195.472194.457191.064187.538188.714190.812190.386189.488192.748195.212207.181180.341179.942179.69179.785181.94185.237187.565188.851187.367185.23184.771185.742186.529NA188.138NANA
us-gaap:Goodwill █████████▇▇▇▅▅▅▅▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁621.6621.6621.6621.6621.6621.6621.6622.6623.5546.3546.7546.4445.6445.6444.704445.028444.327212.82212.82212.82204.481204.481204.523204.409204.375204.375205.574204.646183.673183.673183.673183.673183.673183.673183.673183.673183.673183.673183.673183.673183.673NA183.673NANA
us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill ▁▂▃▃▄▅▆▇█▄▄46.148.651.253.856.559.262.165.067.954.656.9NANANA49.1NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:FiniteLivedIntangibleAssetsNet us-gaap:FiniteLivedIntangibleAssetsByMajorClass us-gaap:CoreDepositsNANA51.2NANANA62.165.067.954.656.9NANA59.149.1NANANA9.7NANANA10.6NANANA13.3NANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:LongTermDebt NANA98.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:ConsolidatedEntities us-gaap:ParentNANA98.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:ConsolidatedEntities,us-gaap:DebtInstrument,us-gaap:LongtermDebtType srt:Subsidiaries,fibk:NotePayable1.30MaturingJune12034,us-gaap:NotesPayableOtherPayablesNANA0.6NANANA0.6NANANA0.6NANANA0.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:ConsolidatedEntities,us-gaap:DebtInstrument,us-gaap:LongtermDebtType srt:Subsidiaries,fibk:NotePayable1.30maturingMarch312038,us-gaap:NotesPayableOtherPayablesNANA2.0NANANA2.0NANANA2.0NANANA0.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LongTermDebtAndCapitalLeaseObligations NANA112.4NANANA13.9NANANA15.8NANANA13.1NANANA27.97NANANA27.885NANANA38.067NANANA36.917NANANA37.16NANANA37.2NANANANANANA
us-gaap:DeferredIncomeTaxLiabilitiesNet ▆▅▇▇█▆▇▆▆▅▃▂▁▁▁▁25.219.927.229.832.224.426.723.624.418.78.63.00.21.70.00.0NANA6.839NANANA9.765NANANA0.0NANANANANANANANANANANANANANANANANANA
us-gaap:TimeDepositsNoncurrent NANA171.1NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:StockholdersEquity █████████▆▆▆▅▅▅▅▅▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁1970.91933.41959.81977.61998.91956.12013.91982.61948.61736.91693.91654.41458.31432.41427.6161419.411405.3781001.596982.593982.504965.125942.014950.493938.575924.855914.45908.924885.864838.526825.638801.581792.86769.954771.373751.186797.87786.335779.275771.02767.955759.345741.697736.802744.703740.188
us-gaap:CommonStocksIncludingAdditionalPaidInCapital ▇▇▇▇█████▆▆▆▅▅▅▅▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁941.6938.5941.1976.81021.21018.71049.31047.81045.6866.6866.7865.5690.7688.0686.991686.508685.289297.173296.071293.96290.366288.782311.72309.167313.125310.544323.596321.132283.697286.553285.535283.352279.232NA271.335NANANANANANANANANANA
us-gaap:RetainedEarningsAccumulatedDeficit ██▇▇▇▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▄▄▃▃▃▃▃▃▃▂▂▂▂▂▁▁▁▁▁▁1005.2988.2962.1938.9912.5897.6953.6921.4892.5874.7851.8828.3802.6776.7752.588731.879718.093707.016694.65679.722664.337648.631638.367623.967612.875599.727587.862572.362560.469546.444532.087517.456499.761483.904463.86458.506448.372441.37435.144427.556421.309NA413.253NANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▅▄▇██▆▄▅▄▃▂▁▁▁▃▄▄▃▃▄▄▄▄▄▄▄▃▃▃▃▃▃▃▄▅▅▅▅▅▅▅24.16.756.661.965.239.811.013.410.5-4.4-24.6-39.4-35.0-32.3-11.9631.0231.996-2.593-8.1288.82210.4224.6010.4065.441-1.1454.179-2.534-7.63-5.64-7.359-16.041-7.948-9.03912.5415.99118.81118.26519.49419.03424.08222.397NA9.375NANA
us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue █▁3.12.4NA1.82.41.4NA2.02.71.91.31.31.81.10.450.951.5910.8771.0260.9651.430.9550.7280.9121.4870.8320.1080.7521.4420.7120.7290.1851.3270.6950.1340.6271.0810.6430.3410.5340.5910.440.2340.342NA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:NetCashProvidedByUsedInOperatingActivities ▄▅▆█▁▄▅▃▂▄▄▅▄▅▄▂▃▅▄▄▃▃▄▃▃▂▄▃▃▃▄▄▃▄▄▄▃▃▄▃▃▅▃▄35.670.5105.5153.6-32.141.370.68.60.547.648.374.234.363.459.9896.14415.51773.03339.01642.20216.67520.17753.46133.78429.507-1.35257.22733.838.30322.02839.48954.78316.20439.74950.88547.7098.93828.2943.6949.75223.31266.34327.22234.314NA
us-gaap:NetCashProvidedByUsedInInvestingActivities ▄▃▆▆▁▇▆▇█▇▇▇▇▆▆▇▇▇▇▇▇▇▇▇▇▇▆▇▆▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇-715.5-959.2-233.7-256.2-1406.126.2-167.9-106.0245.012.1-77.71.320.8-126.7-174.615.49349.223-10.671-57.5960.516-61.311-84.707-84.96948.8473.857-63.074-168.95767.364-121.8227.571-96.772-63.5270.082-44.72-99.742-106.296-3.64268.601-80.843-12.288-43.95311.145-65.61-88.765NA
us-gaap:NetCashProvidedByUsedInFinancingActivities ▃▄▄▄█▁▂▃▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▂▁▂▂▃▂▂▂▂▁▁▃▂▂▂▂▂▁▂▂▂432.3807.9544.4538.21994.0-275.1-95.5238.1-71.873.5-113.6177.5-87.348.6-9.226-48.57947.083-36.43399.23122.598-134.841-60.399103.67119.23-164.733-96.44190.437215.1216.63426.10549.767182.87-146.612-297.818238.854133.269-91.56753.5865.36991.272-244.189-82.785181.65194.322NA
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect ▁▂▇▇█▁▁▄▅▄▂▅-247.6-80.8416.2435.6555.8-207.6-192.8140.7173.7133.2-143.0253.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:DeferredIncomeTaxExpenseBenefit ▃▅▃▃▃▃▄▃▃▄▄▄▃▅▃█▁▄▄▃▃▃▃▄▄▄▃▄▃▄▄▄▄▄▃▄▄▃▄▃▃▃▁▃-0.69.60.5-1.3-1.4-4.44.9-2.20.02.72.63.9-0.810.11.14635.599-17.8482.023.713-0.6650.838-0.517-0.5263.8674.1944.914-3.1924.7771.132.634.9742.8461.6031.8530.7492.9835.312-0.2822.0050.9380.321-0.859-14.276-1.758NA
us-gaap:DepreciationDepletionAndAmortization ▇████▇▇▇█▅▅▅▅▅▁▆▄▃▄▄▄▄▃▃▃▃▄▃▃▃▃▃▃▃▃▃▃▃▃▃10.911.412.111.811.59.79.79.711.87.57.76.86.56.60.5128.2555.0544.6114.9984.9914.8124.6794.6114.6124.5464.5444.6874.3823.893.8963.9523.9954.0954.2034.3424.2024.2664.3024.3714.32NANANANANA
us-gaap:NetCashProvidedByUsedInOperatingActivities ▄▅▆█▁▄▅▃▂▄▄▅▄▅▄▂▃▅▄▄▃▃▄▃▃▂▄▃▃▃▄▄▃▄▄▄▃▃▄▃▃▅▃▄35.670.5105.5153.6-32.141.370.68.60.547.648.374.234.363.459.9896.14415.51773.03339.01642.20216.67520.17753.46133.78429.507-1.35257.22733.838.30322.02839.48954.78316.20439.74950.88547.7098.93828.2943.6949.75223.31266.34327.22234.314NA
us-gaap:NetIncomeLoss ▆█▇▇▆▄█▇▆▆▆▆▆▆▅▄▃▄▄▄▄▃▄▃▃▃▃▃▃▃▃▄▃▃▃▂▂▂▂▂▁▁▂▁▁42.551.446.948.336.729.352.449.137.941.640.441.441.736.734.26827.25921.86823.12624.76525.19325.55420.12423.43120.16222.22220.9822.77619.15521.07721.39320.77523.81221.50520.04416.84516.15513.0112.21413.26511.9219.8549.50610.8388.7296.659
us-gaap:ShareBasedCompensation █▆▅▅▆▄▄▅▇▅▄▄▅▃▂▃▄▃▃▃▄▃▂▃▄▃▁▃▄▂▂▁▄▂▁▂▃▂▂▂▂▂▂▂3.12.41.91.82.41.41.42.02.71.91.31.41.81.10.450.951.5910.8771.0260.9651.430.9550.7280.9121.4870.8320.1080.7521.4420.7120.7290.1851.3270.6950.1340.6271.0810.6430.4630.5320.7050.4110.3740.402NA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:NetCashProvidedByUsedInInvestingActivities ▄▃▆▆▁▇▆▇█▇▇▇▇▆▆▇▇▇▇▇▇▇▇▇▇▇▆▇▆▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇-715.5-959.2-233.7-256.2-1406.126.2-167.9-106.0245.012.1-77.71.320.8-126.7-174.615.49349.223-10.671-57.5960.516-61.311-84.707-84.96948.8473.857-63.074-168.95767.364-121.8227.571-96.772-63.5270.082-44.72-99.742-106.296-3.64268.601-80.843-12.288-43.95311.145-65.61-88.765NA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
us-gaap:NetCashProvidedByUsedInFinancingActivities ▃▄▄▄█▁▂▃▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▂▁▂▂▃▂▂▂▂▁▁▃▂▂▂▂▂▁▂▂▂432.3807.9544.4538.21994.0-275.1-95.5238.1-71.873.5-113.6177.5-87.348.6-9.226-48.57947.083-36.43399.23122.598-134.841-60.399103.67119.23-164.733-96.44190.437215.1216.63426.10549.767182.87-146.612-297.818238.854133.269-91.56753.5865.36991.272-244.189-82.785181.65194.322NA
us-gaap:PaymentsOfDividendsCommonStock ▄▄▄▄▃█▃▃▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▂▂▂▂▂▂▂▂25.525.323.721.921.861.220.220.220.118.716.915.715.815.713.55913.47310.79110.769.8379.8089.8489.869.0319.079.0749.1157.2767.2627.0527.0366.1446.1175.6480.010.765.1585.1555.1354.8144.8124.8094.7984.7584.816NA
us-gaap:PaymentsForRepurchaseOfCommonStock ▁▂▇█▁▆▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▅▁▂▁▃▁▁▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁0.05.437.946.30.032.60.00.00.12.40.00.10.00.90.410.0470.0320.8590.7350.0770.73325.3090.0995.2840.015.2640.0030.9725.6053.1590.00.00.00.4480.0010.0050.0010.2560.0510.0040.0290.1640.00.0NA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
 us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:ConsolidatedEntities,us-gaap:Range,us-gaap:DebtInstrument srt:Subsidiaries,srt:Maximum,fibk:NotePayableSixPointTwoFourPercentNANA3.25e-06NANANA6.24e-08NANANA6.24e-08NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:ConsolidatedEntities,us-gaap:Range,us-gaap:DebtInstrument srt:Subsidiaries,srt:Minimum,fibk:NotePayableSixPointTwoFourPercentNANA1e-06NANANA1e-08NANANA1e-08NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA

Common Stock Shares Authorized

us-gaap:CommonStockSharesAuthorized us-gaap:StatementClassOfStock

us-gaap:CommonStockSharesAuthorized

us-gaap:CommonClassA


Common
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312010-03-052010-03-04
Value10010010010010010010010010020
Percentage of CommonStockSharesAuthorized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value61616364646564605856565648454444454545454544444443434343424242
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value61616364646464605856565647444444444545454444434343434242424242
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:PerformanceShares


Antidilutive
Period End2021-03-312020-03-312019-03-312018-03-312017-03-312016-03-312015-03-31
Value368790.0309410.0154390.0164020.0187680.0226820.0166770.0
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount100.0100.0100.0100.0100.0100.0100.0

us-gaap:RestrictedStock


Antidilutive
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-03-312014-03-312013-03-312012-03-31
Value84165.092602.068397.0108370.0113470.04808.0761.0121450.04376.085.0139940.0096262.096897.0135.096726.040865.05884.0166770.0111420.061760.048196.0
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount0.025.10.00.036.70.00.078.70.00.085.30.00.051.60.00.018.00.0100.00.00.00.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0.690.830.750.760.570.450.810.760.590.690.670.710.740.650.610.490.460.520.560.570.580.450.520.450.490.460.50.430.480.490.480.540.490.460.380.360.280.260.290.260.210.20.240.180.14
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0.690.830.750.760.570.450.80.760.590.690.660.710.740.650.60.480.450.510.550.560.570.450.510.440.490.460.50.420.470.480.470.540.490.460.370.350.280.260.290.260.210.20.240.180.14
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Tier One Risk Based Capital To Risk Weighted Assets

us-gaap:TierOneRiskBasedCapitalToRiskWeightedAssets

us-gaap:TierOneRiskBasedCapitalToRiskWeightedAssets


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value12.1712.2812.3312.560.12850.1280.13410.13010.12730.1250.12260.120110.121470.120660.11930.1190.11690.13750.13890.1360.1370.1370.140.1380.1390.1390.1450.1470.150.1520.1490.1480.1450.1410.1360.1450.1420.146
Percentage of TierOneRiskBasedCapitalToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TierOneRiskBasedCapitalToRiskWeightedAssets dei:LegalEntity

fibk:FirstInterstateBank


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value11.611.7811.9311.930.120.11710.11810.11620.11560.11430.11270.114660.11370.114080.11460.11910.11810.12320.11940.1270.1270.130.1310.130.130.1320.1370.1340.1320.1330.1320.1340.1340.1320.130.1280.1260.122
Percentage of TierOneRiskBasedCapitalToRiskWeightedAssets95.395.996.895.093.491.588.189.390.891.491.995.593.694.596.1100.1101.089.686.093.492.794.993.694.293.595.094.591.288.087.588.690.592.493.695.688.388.783.6

Capital To Risk Weighted Assets

us-gaap:CapitalToRiskWeightedAssets

us-gaap:CapitalToRiskWeightedAssets


Capital
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value13.8914.0414.1914.450.14760.13670.1410.13710.13430.13230.12990.12760.129750.129040.12760.12760.12560.14940.15130.1490.150.150.1540.1530.1540.1540.1620.1630.1670.1680.1680.1670.1630.1590.1560.1650.1620.165
Percentage of CapitalToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalToRiskWeightedAssets dei:LegalEntity

fibk:FirstInterstateBank


Capital
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value12.4712.6712.8912.910.12990.12580.1250.12330.12270.12160.12010.122830.122020.122490.12290.12780.130.13520.13130.1390.1390.1420.1440.1430.1430.1450.1510.1480.1460.1470.1470.1490.1490.1470.1460.1440.1420.138
Percentage of CapitalToRiskWeightedAssets89.890.290.889.388.092.088.789.991.491.992.596.394.094.996.3100.2103.590.586.893.392.794.793.593.592.994.293.290.887.487.587.589.291.492.593.687.387.783.6

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax


Comprehensive
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value591.5414562585052526155373919212626287.81523312418261627271722301224-0.07416141611128.21713229.779-2.7359.791
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating48.61.231.134.948.243.935.736.837.247.341.930.534.618.119.624.230.838.510.031.543.633.625.237.824.240.339.624.635.548.019.639.0-0.125.520.724.517.118.411.418.530.713.2-3.612.4

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

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value5565616347376864485352535347494033323737393035303331352932323136323025241918201714
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating44.752.346.148.936.628.449.245.634.340.639.744.147.443.745.537.739.343.848.350.754.541.948.042.748.445.749.841.950.452.549.257.951.547.538.136.128.326.527.923.919.7

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value12141414108.216151011111211101513119.451121213101110111012101111111311108.9318.4686.5276.1126.7955.6554.6724.4935.23.862.628
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating10.211.311.111.48.16.211.810.87.78.79.010.010.59.613.912.613.812.716.617.119.014.115.914.216.515.217.514.417.618.417.120.617.916.713.212.49.58.99.47.76.46.16.84.93.3

Income Taxes Paid

us-gaap:IncomeTaxesPaid

us-gaap:IncomeTaxesPaid


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
Value1421181113111610240.09.56.15.14.64.489.9-14.371281412234.2060.08.885135.15.554.91160.09.359.691173.3764.80.0120.14.223.698.730.0223.67
Percentage of IncomeTaxesPaid100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.0100.0
Percentage of InterestAndDividendIncomeOperating11.916.813.88.910.18.711.77.317.20.07.25.04.54.34.19.1-16.738.617.917.132.55.80.012.619.17.47.97.025.20.014.415.227.35.27.10.018.30.15.95.011.90.028.94.6

Interest And Fee Income Loans And Leases

us-gaap:InterestAndFeeIncomeLoansAndLeases

us-gaap:InterestAndFeeIncomeLoansAndLeases


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value105107117112112112118120120111112103969193947363686562626462605961615553555454555757585760616162656767
Percentage of InterestAndFeeIncomeLoansAndLeases100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating85.586.087.587.187.084.784.784.985.185.385.385.785.485.285.786.486.185.687.287.687.086.887.887.786.686.386.887.586.685.785.785.985.885.385.084.284.183.984.183.583.684.585.384.984.5

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value4.54.65.35.96.39.11115161412119.27.87.857.9746.5465.5644.5514.3544.3264.434.7134.454.434.4674.9514.6464.4584.5514.7364.9735.1965.796.6287.177.8938.4238.9719.9911112131516
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating3.63.74.04.64.96.98.411.211.811.29.79.28.17.27.27.37.67.55.85.86.06.16.46.36.46.57.06.76.97.37.37.88.18.99.810.511.412.212.513.615.016.317.519.320.9

Interest Income Expense Net

us-gaap:InterestIncomeExpenseNet

us-gaap:InterestIncomeExpenseNet


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value118120128123122123128125125116118110103991001007968737067676866656465655958595858596061616063636261626363
Percentage of InterestIncomeExpenseNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating96.496.396.095.495.193.191.688.888.288.890.390.891.992.892.892.792.492.594.294.294.093.993.693.793.693.593.093.393.192.792.792.291.991.190.289.588.687.887.586.485.083.782.580.779.1

Interest Paid Net

us-gaap:InterestPaidNet

us-gaap:InterestPaidNet


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value6.33.57.56.77.810121514121110
Percentage of InterestPaidNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating5.12.85.65.26.18.28.611.310.19.58.88.8

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value425146483629524937414041413634272123242525202320222022192121202321201616131213119.8549.506108.7296.659
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating34.541.035.137.528.522.237.434.726.731.930.734.236.934.131.525.125.531.131.733.635.527.832.028.531.930.532.327.532.834.132.137.233.630.824.923.718.817.718.416.213.412.914.211.18.3

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value425146483629524937414041413634272123242525202320222022192121202321201616131213119.8549.506108.729
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.9100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating34.541.035.137.528.522.237.434.726.731.930.734.236.934.131.525.125.531.131.733.635.527.832.028.531.930.532.327.532.834.132.137.233.630.824.923.718.817.718.416.213.412.914.211.1
Percentage of InterestAndDividendIncomeOperating us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value17-49.9-3.32528-2.42.9142014-4.4-2.6-17.2-0.9734.5895.535-16.95-1.65.8214.195-5.0356.586-5.3246.7135.096-1.991.7198.682-8.0931.09-21.579-3.451-2.820.546-1.230.46-5.0481.68512
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating14.1-39.8-2.619.721.8-1.72.110.515.511.2-3.6-2.3-16.0-0.95.37.4-21.7-2.18.15.8-6.99.3-7.69.87.2-2.92.713.8-12.51.7-33.7-5.3-4.20.8-1.80.7-7.02.317.3

Revenue From Contract With Customer Excluding Assessed Tax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax

us-gaap:CreditAndDebitCard


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value111011109.3101010109.49.8101210121210
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating9.28.18.38.17.27.77.77.67.47.27.48.311.49.811.311.411.9
Percentage of InterestAndDividendIncomeOperating us-gaap:CreditAndDebitCard0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:DepositAccount


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value3.93.84.34.33.65.45.45.35.45.05.25.75.35.66.05.95.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax34.237.338.741.038.752.950.049.151.453.253.156.441.153.348.847.650.0
Percentage of InterestAndDividendIncomeOperating3.23.03.23.32.84.13.93.83.83.84.04.74.75.25.55.45.9
Percentage of InterestAndDividendIncomeOperating us-gaap:DepositAccount0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FinancialServiceOther


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value1.62.12.15.02.94.74.44.24.24.34.03.43.83.93.73.63.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax14.020.618.947.631.246.140.738.940.045.740.833.729.537.130.129.033.3
Percentage of InterestAndDividendIncomeOperating1.31.71.63.92.33.63.13.03.03.33.02.83.43.63.43.34.0
Percentage of InterestAndDividendIncomeOperating us-gaap:FinancialServiceOther0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value18940184431764817069164711441114644147011441413498133001335512235122731221312206122369061906389738605869087288604838685288609848176517617756475007291743977217461730573947325730772027500
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidatedEntities

srt:ParentCompany


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value2212215718261562
Percentage of Assets12.514.713.712.8
Percentage of Assets12.514.713.712.8
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

Liabilities

us-gaap:Liabilities

us-gaap:Liabilities


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value16969165101568815091144721245512630127191246611761116061170110777108411078510787108308059808179917640774877777665746176147701759568126792676367076521666769706663651866156554653964436764
Percentage of Liabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets89.689.588.988.487.986.486.286.586.587.187.387.688.188.388.388.488.588.989.289.188.889.289.189.189.089.389.489.689.089.289.489.489.489.690.389.389.289.589.589.589.590.2

us-gaap:Liabilities us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilitiesus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value252143132134
Percentage of Liabilities1.61.11.11.2
Percentage of Assets1.41.01.01.1
Percentage of Assets srt:ParentCompany11.46.67.38.6

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value18940184431764817069164711441114644147011441413498133001335512235122731221312206122369061906389738605869087288604838685288609848176517617756475007291743977217461730573947325730772027500
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-312017-12-31
Value2212215718261562
Percentage of LiabilitiesAndStockholdersEquity12.514.713.712.8
Percentage of Assets12.514.713.712.8
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value197019331959197719981956201319821948173616931654145814321427141914051001982982965942950938924914908885838825801792769771751797786779771767759741736744740574539
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 Assets10.410.511.111.612.113.613.813.513.512.912.712.411.911.711.711.611.511.110.810.911.210.810.910.911.010.710.610.411.010.810.610.610.610.49.710.710.810.510.510.510.50.09.80.00.00.00.0

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value1959201316931427
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets11.113.812.711.7
Percentage of Assets srt:ParentCompany88.693.492.791.4

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-31
Value6.36.85662653910129.9-5.1-25.5-13.2-10.1
Percentage of StockholdersEquity0.30.42.93.13.32.00.50.70.5-0.3-1.5-0.9-1.0
Percentage of Assets0.00.00.30.40.40.30.10.10.1-0.0-0.2-0.1-0.1
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value246.756616539111310-4.4-24.6-39.4-35.0-32.3-11.9631.0231.996-2.593-8.1288.822104.6010.4065.441-1.1454.179-2.534-7.63-5.64-7.359-16.041-7.948-9.03912151818191924229.6489.3752221158.972
Percentage of StockholdersEquity1.20.32.93.13.32.00.50.70.5-0.3-1.5-2.4-2.4-2.3-0.80.10.1-0.3-0.80.91.10.50.00.6-0.10.5-0.3-0.9-0.7-0.9-2.0-1.0-1.21.62.12.42.32.52.53.12.91.31.33.13.02.61.7
Percentage of Assets0.10.00.30.40.40.30.10.10.1-0.0-0.2-0.3-0.3-0.3-0.10.00.0-0.0-0.10.10.10.10.00.1-0.00.0-0.0-0.1-0.1-0.1-0.2-0.1-0.10.20.20.30.30.30.30.30.30.00.10.00.00.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStockIncludingAdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value94193894197610211018104910471045866866865690688686686685297296293290288311309313310323321283286285283279274271270269268266266265264264263263112117
Percentage of StockholdersEquity47.848.548.049.451.152.152.152.853.749.951.252.347.448.048.148.448.829.730.129.930.130.732.832.933.934.035.636.333.834.735.635.736.335.636.133.934.334.434.634.735.035.735.935.435.619.521.8
Percentage of Assets5.05.15.35.76.27.17.27.17.36.46.56.55.65.65.65.65.63.33.33.33.43.33.63.63.73.63.83.83.73.83.83.83.83.73.53.63.73.63.63.63.70.03.50.00.00.00.0
Percentage of Assets us-gaap:CommonStockIncludingAdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value1005988962938912897181921892874851828802776752731718707694679664648638623612599587572560546532517499483463458448441435427421417413408404397362
Percentage of StockholdersEquity51.051.149.147.545.745.99.046.545.850.450.350.155.054.252.751.651.170.670.769.268.868.967.266.566.365.664.764.666.866.266.465.364.962.761.857.557.056.656.455.755.556.256.154.854.769.267.2
Percentage of Assets5.35.45.55.55.56.21.26.36.26.56.46.26.66.36.26.05.97.87.77.67.77.57.37.37.37.06.86.77.37.27.06.96.96.56.06.16.16.05.95.95.80.05.50.00.00.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Tier One Risk Based Capital

us-gaap:TierOneRiskBasedCapital

us-gaap:TierOneRiskBasedCapital


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value14151396136913781393136714221385134612371212118110861058104010261011880894877867848861843835738807808765753739722699677652695683704
Percentage of TierOneRiskBasedCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets7.57.67.88.18.59.59.79.49.39.29.18.88.98.68.58.48.39.79.99.810.19.89.99.810.08.79.49.510.09.99.89.69.69.18.59.39.49.6

us-gaap:TierOneRiskBasedCapital dei:LegalEntity

fibk:FirstInterstateBank


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value13451336132013051297124712481233122011291111103410139979941022748785765817798799805788776770754679668657650648643634622612602588
Percentage of TierOneRiskBasedCapital95.095.796.494.793.191.287.889.190.691.291.787.593.394.295.699.774.189.285.693.292.194.293.693.593.0104.493.584.087.387.387.989.892.093.695.388.088.183.5
Percentage of Assets7.17.27.57.67.98.78.58.48.58.48.47.78.38.18.18.46.18.78.49.19.39.29.29.29.39.08.88.08.78.68.68.68.88.58.18.28.28.0
Percentage of Assets fibk:FirstInterstateBank0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value19482196227618601425869107612691128955822965712758
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets10.311.912.910.98.76.07.48.67.87.16.27.25.86.2

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents us-gaap:ConsolidatedEntities

srt:ParentCompany


Cash
Period End2020-12-312019-12-312018-12-312017-12-31
Value1231477242
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents5.413.78.95.6
Percentage of Assets0.71.00.50.3
Percentage of Assets srt:ParentCompany5.66.84.02.7

Property Plant And Equipment Gross

us-gaap:PropertyPlantAndEquipmentGross

us-gaap:PropertyPlantAndEquipmentGross


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value491475422404346332324303303291
Percentage of PropertyPlantAndEquipmentGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.83.23.23.33.83.83.84.03.94.0

us-gaap:PropertyPlantAndEquipmentGross us-gaap:PropertyPlantAndEquipmentByType

us-gaap:BuildingAndBuildingImprovements


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value349330268257218213209196195188
Percentage of PropertyPlantAndEquipmentGross71.169.563.563.663.064.164.464.964.564.7
Percentage of Assets2.02.32.02.12.42.42.42.62.52.6
Percentage of Assets us-gaap:BuildingAndBuildingImprovements0.00.00.00.00.00.00.00.00.00.0

us-gaap:FurnitureAndFixtures


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value889410497888174686863
Percentage of PropertyPlantAndEquipmentGross18.119.824.624.225.524.523.122.722.722.0
Percentage of Assets0.50.60.80.81.00.90.90.90.90.9
Percentage of Assets us-gaap:FurnitureAndFixtures0.00.00.00.00.00.00.00.00.00.0

us-gaap:Land


Property
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value52504949393740373838
Percentage of PropertyPlantAndEquipmentGross10.810.711.812.211.511.412.512.412.813.3
Percentage of Assets0.30.30.40.40.40.40.50.50.50.5
Percentage of Assets us-gaap:Land0.00.00.00.00.00.00.00.00.00.0

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value179169176162152141129123115106
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.01.21.31.31.71.61.51.61.51.5

Amortization Of Intangible Assets

us-gaap:AmortizationOfIntangibleAssets

us-gaap:AmortizationOfIntangibleAssets


Amortization
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value2.52.52.5999999999999992.72.72.92.93.03.02.32.42.01.71.81.8611.8851.0620.630.8980.8750.8270.8270.8370.8420.8540.8550.8550.6880.3540.3540.3540.3550.3550.3540.3540.3550.3550.3550.3610.3620.3610.362
Percentage of AmortizationOfIntangibleAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value299305312307309308306302321298245244233240241242243195194191187188190190189192195207180179179179181185187188187185184185186188
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.61.71.81.81.92.12.12.12.22.21.81.81.92.02.02.02.02.22.12.12.22.22.22.22.32.32.32.42.42.42.42.42.52.52.42.52.62.52.52.52.62.5

Goodwill

us-gaap:Goodwill

us-gaap:Goodwill


Goodwill
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value621621621621621621621622623546546546445445444445444212212212204204204204204204205204183183183183183183183183183183183183183183
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.33.43.53.63.84.34.24.24.34.04.14.13.63.63.63.63.62.32.32.42.42.42.32.42.42.42.42.42.42.42.42.42.52.52.42.52.52.52.52.52.62.4

Indefinite Lived Intangible Assets Excluding Goodwill

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill


Indefinite
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-31
Value464851535659626567545649
Percentage of IndefiniteLivedIntangibleAssetsExcludingGoodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.20.30.30.30.30.40.40.40.50.40.40.4

Finite Lived Intangible Assets Net

us-gaap:FiniteLivedIntangibleAssetsNet us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:FiniteLivedIntangibleAssetsNet

us-gaap:CoreDeposits


Finite
Period End2020-12-312019-12-312019-09-302019-06-302019-04-082019-03-312018-12-312018-03-312017-12-312016-12-312015-12-312014-12-31
Value516265673.0545659499.71013
Percentage of FiniteLivedIntangibleAssetsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.40.40.50.00.40.40.50.40.10.10.2
Percentage of Assets us-gaap:CoreDeposits0.00.00.00.00.00.00.00.00.00.00.00.0

Other Assets

us-gaap:OtherAssets

us-gaap:OtherAssets


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value254223215227236221187196181162159153152142145149148108818192827879747773686261615456636259656768696981
Percentage of OtherAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.31.21.21.31.41.51.31.31.31.21.21.21.21.21.21.21.21.20.90.91.11.00.90.90.90.90.90.80.80.80.80.70.80.80.80.80.90.90.91.01.01.1

us-gaap:OtherAssets us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value61615961
Percentage of OtherAssets28.532.937.142.3
Percentage of Assets0.30.40.40.5
Percentage of Assets srt:ParentCompany2.82.93.24.0

Long Term Debt

us-gaap:LongTermDebt

us-gaap:LongTermDebt


Long
Period End2020-12-31
Value98
Percentage of LongTermDebt100.0
Percentage of Assets0.6

us-gaap:LongTermDebt us-gaap:ConsolidatedEntities

us-gaap:Parent


Long
Period End2020-12-31
Value98
Percentage of LongTermDebt100.0
Percentage of Assets0.6
Percentage of Assets us-gaap:Parent0.0

us-gaap:LongTermDebt us-gaap:ConsolidatedEntities, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

srt:Subsidiaries, fibk:NotePayable1.30MaturingJune12034, us-gaap:NotesPayableOtherPayables


Long
Period End2020-12-312019-12-312018-12-312017-12-31
Value0.60.60.60.0
Percentage of LongTermDebt0.60.00.00.0
Percentage of Assets0.00.00.00.0
Percentage of Assets srt:Subsidiaries fibk:NotePayable1.30MaturingJune12034 us-gaap:NotesPayableOtherPayables0.00.00.00.0

srt:Subsidiaries, fibk:NotePayable1.30maturingMarch312038, us-gaap:NotesPayableOtherPayables


Long
Period End2020-12-312019-12-312018-12-312017-12-31
Value2.02.02.00.0
Percentage of LongTermDebt2.00.00.00.0
Percentage of Assets0.00.00.00.0
Percentage of Assets srt:Subsidiaries fibk:NotePayable1.30maturingMarch312038 us-gaap:NotesPayableOtherPayables0.00.00.00.0

Long Term Debt And Capital Lease Obligations

us-gaap:LongTermDebtAndCapitalLeaseObligations

us-gaap:LongTermDebtAndCapitalLeaseObligations


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value112131513272738363737
Percentage of LongTermDebtAndCapitalLeaseObligations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.60.10.10.10.30.30.40.50.50.5

Deferred Income Tax Liabilities Net

us-gaap:DeferredIncomeTaxLiabilitiesNet

us-gaap:DeferredIncomeTaxLiabilitiesNet


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312015-12-312014-12-31
Value251927293224262324188.63.00.21.70.00.06.8399.7650.0
Percentage of DeferredIncomeTaxLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0100.0100.00.0
Percentage of Assets0.10.10.20.20.20.20.20.20.20.10.10.00.00.00.00.00.10.10.0

Time Deposits Noncurrent

us-gaap:TimeDepositsNoncurrent

us-gaap:TimeDepositsNoncurrent


Time
Period End2020-12-31
Value171
Percentage of TimeDepositsNoncurrent100.0
Percentage of Assets1.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value197019331959197719981956201319821948173616931654145814321427141914051001982982965942950938924914908885838825801792769771751797786779771767759741736744740574539
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 Assets10.410.511.111.612.113.613.813.513.512.912.712.411.911.711.711.611.511.110.810.911.210.810.910.911.010.710.610.411.010.810.610.610.610.49.710.710.810.510.510.510.50.09.80.00.00.00.0

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value1959201316931427
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets11.113.812.711.7
Percentage of Assets srt:ParentCompany88.693.492.791.4

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-31
Value6.36.85662653910129.9-5.1-25.5-13.2-10.1
Percentage of StockholdersEquity0.30.42.93.13.32.00.50.70.5-0.3-1.5-0.9-1.0
Percentage of Assets0.00.00.30.40.40.30.10.10.1-0.0-0.2-0.1-0.1
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value246.756616539111310-4.4-24.6-39.4-35.0-32.3-11.9631.0231.996-2.593-8.1288.822104.6010.4065.441-1.1454.179-2.534-7.63-5.64-7.359-16.041-7.948-9.03912151818191924229.6489.3752221158.972
Percentage of StockholdersEquity1.20.32.93.13.32.00.50.70.5-0.3-1.5-2.4-2.4-2.3-0.80.10.1-0.3-0.80.91.10.50.00.6-0.10.5-0.3-0.9-0.7-0.9-2.0-1.0-1.21.62.12.42.32.52.53.12.91.31.33.13.02.61.7
Percentage of Assets0.10.00.30.40.40.30.10.10.1-0.0-0.2-0.3-0.3-0.3-0.10.00.0-0.0-0.10.10.10.10.00.1-0.00.0-0.0-0.1-0.1-0.1-0.2-0.1-0.10.20.20.30.30.30.30.30.30.00.10.00.00.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStockIncludingAdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value94193894197610211018104910471045866866865690688686686685297296293290288311309313310323321283286285283279274271270269268266266265264264263263112117
Percentage of StockholdersEquity47.848.548.049.451.152.152.152.853.749.951.252.347.448.048.148.448.829.730.129.930.130.732.832.933.934.035.636.333.834.735.635.736.335.636.133.934.334.434.634.735.035.735.935.435.619.521.8
Percentage of Assets5.05.15.35.76.27.17.27.17.36.46.56.55.65.65.65.65.63.33.33.33.43.33.63.63.73.63.83.83.73.83.83.83.83.73.53.63.73.63.63.63.70.03.50.00.00.00.0
Percentage of Assets us-gaap:CommonStockIncludingAdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value1005988962938912897181921892874851828802776752731718707694679664648638623612599587572560546532517499483463458448441435427421417413408404397362
Percentage of StockholdersEquity51.051.149.147.545.745.99.046.545.850.450.350.155.054.252.751.651.170.670.769.268.868.967.266.566.365.664.764.666.866.266.465.364.962.761.857.557.056.656.455.755.556.256.154.854.769.267.2
Percentage of Assets5.35.45.55.55.56.21.26.36.26.56.46.26.66.36.26.05.97.87.77.67.77.57.37.37.37.06.86.77.37.27.06.96.96.56.06.16.16.05.95.95.80.05.50.00.00.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stocks Including Additional Paid In Capital

us-gaap:CommonStocksIncludingAdditionalPaidInCapital

us-gaap:CommonStocksIncludingAdditionalPaidInCapital


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value94193894197610211018104910471045866866865690688686686685297296293290288311309313310323321283286285283279271
Percentage of CommonStocksIncludingAdditionalPaidInCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.05.15.35.76.27.17.27.17.36.46.56.55.65.65.65.65.63.33.33.33.43.33.63.63.73.63.83.83.73.83.83.83.83.5

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1005988962938912897953921892874851828802776752731718707694679664648638623612599587572560546532517499483463458448441435427421413
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.35.45.55.55.56.26.56.36.26.56.46.26.66.36.26.05.97.87.77.67.77.57.37.37.37.06.86.77.37.27.06.96.96.56.06.16.16.05.95.95.85.5

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value246.756616539111310-4.4-24.6-39.4-35.0-32.3-11.9631.0231.996-2.593-8.1288.822104.6010.4065.441-1.1454.179-2.534-7.63-5.64-7.359-16.041-7.948-9.03912151818191924229.375
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.00.30.40.40.30.10.10.1-0.0-0.2-0.3-0.3-0.3-0.10.00.0-0.0-0.10.10.10.10.00.1-0.00.0-0.0-0.1-0.1-0.1-0.2-0.1-0.10.20.20.30.30.30.30.30.30.1

Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue


Adjustments
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3100000.02400000.01800000.02400000.01400000.02000000.02700000.01900000.01300000.01300000.01800000.01100000.0450000.0950000.01591000.0877000.01026000.0965000.01430000.0955000.0728000.0912000.01487000.0832000.0108000.0752000.01442000.0712000.0729000.0185000.01327000.0695000.0134000.0627000.01081000.0643000.0341000.0534000.0591000.0440000.0234000.0342000.0
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents

us-gaap:CommonStockIncludingAdditionalPaidInCapital


Adjustments
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3100000.02400000.01800000.02400000.01400000.02000000.02700000.01900000.01300000.01800000.01100000.0450000.0950000.01591000.0877000.01026000.0965000.01430000.0955000.0728000.0912000.01487000.0832000.0108000.0752000.01442000.0712000.0729000.0185000.01327000.0695000.0134000.0627000.01081000.0643000.0341000.0534000.0591000.0440000.0234000.0342000.0
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStockIncludingAdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3570105153-32.141708.60.54748743463596.144157339421620533329-1.35257338.303223954163950478.93828439.75223662734
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating28.956.378.9119.2-24.931.250.46.10.436.436.761.230.458.955.25.618.198.149.956.323.227.973.147.742.3-2.081.248.512.935.161.085.725.361.175.370.012.941.060.713.331.789.835.743.5

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-715.5-959.2-233.7-256.2-1406.126-167.9-106.024512-77.71.320-126.7-174.615.49349-10.671-57.5960-61.311-84.707-84.969483.857-63.074-168.95767-121.8227-96.772-63.5270.082-44.72-99.742-106.296-3.64268-80.843-12.288-43.95311-65.61-88.765
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating-580.3-765.5-174.8-198.8-1091.719.8-119.9-75.0172.49.3-59.01.118.4-117.8-160.75.157.3-14.3-73.780.8-85.2-117.0-116.269.05.5-91.7-239.896.6-189.844.0-149.5-99.40.1-68.7-147.5-155.9-5.399.3-112.3-16.7-59.815.1-86.1-112.4

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value4328075445381994-275.1-95.5238-71.873-113.6177-87.348-9.226-48.57947-36.43399122-134.841-60.399103119-164.733-96.441902156.6342649182-146.612-297.818238133-91.567535.36991-244.189-82.78518194
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating350.6644.8407.2417.51548.1-208.1-68.2168.5-50.556.3-86.3146.5-77.345.2-8.5-44.754.8-48.9127.0163.6-187.4-83.4141.8168.5-236.3-140.2128.3308.510.341.676.9286.1-229.2-457.7353.3195.5-132.677.67.5124.2-332.0-112.1238.3119.4

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value-247.6-80.8416435555-207.6-192.8140173133-143.0253
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating-200.8-64.5311.3337.9431.5-157.0-137.799.6122.2102.0-108.7208.7

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DeferredIncomeTaxExpenseBenefit


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-0.69.60.5-1.3-1.4-4.44.9-2.20.02.72.63.9-0.8101.14635-17.8482.023.713-0.6650.838-0.517-0.5263.8674.1944.914-3.1924.7771.132.634.9742.8461.6031.8530.7492.9835.312-0.2822.0050.9380.321-0.859-14.276-1.758
Percentage of DeferredIncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Depreciation Depletion And Amortization

us-gaap:DepreciationDepletionAndAmortization

us-gaap:DepreciationDepletionAndAmortization


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-30
Value10111211119.79.79.7117.57.76.86.56.60.5128.2555.0544.6114.9984.9914.8124.6794.6114.6124.5464.5444.6874.3823.893.8963.9523.9954.0954.2034.3424.2024.2664.3024.3714.32
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3570105153-32.141708.60.54748743463596.144157339421620533329-1.35257338.303223954163950478.93828439.75223662734
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating28.956.378.9119.2-24.931.250.46.10.436.436.761.230.458.955.25.618.198.149.956.323.227.973.147.742.3-2.081.248.512.935.161.085.725.361.175.370.012.941.060.713.331.789.835.743.5

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value425146483629524937414041413634272123242525202320222022192121202321201616131213119.8549.506108.7296.659
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating34.541.035.137.528.522.237.434.726.731.930.734.236.934.131.525.125.531.131.733.635.527.832.028.531.930.532.327.532.834.132.137.233.630.824.923.718.817.718.416.213.412.914.211.18.3

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value425146483629524937414041413634272123242525202320222022192121202321201616131213119.8549.506108.729
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.9100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating34.541.035.137.528.522.237.434.726.731.930.734.236.934.131.525.125.531.131.733.635.527.832.028.531.930.532.327.532.834.132.137.233.630.824.923.718.817.718.416.213.412.914.211.1
Percentage of InterestAndDividendIncomeOperating us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Share Based Compensation

us-gaap:ShareBasedCompensation

us-gaap:ShareBasedCompensation


Share
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
Value3100000.02400000.01900000.01800000.02400000.01400000.01400000.02000000.02700000.01900000.01300000.01400000.01800000.01100000.0450000.0950000.01591000.0877000.01026000.0965000.01430000.0955000.0728000.0912000.01487000.0832000.0108000.0752000.01442000.0712000.0729000.0185000.01327000.0695000.0134000.0627000.01081000.0643000.0463000.0532000.0705000.0411000.0374000.0402000.0
Percentage of ShareBasedCompensation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-715.5-959.2-233.7-256.2-1406.126-167.9-106.024512-77.71.320-126.7-174.615.49349-10.671-57.5960-61.311-84.707-84.969483.857-63.074-168.95767-121.8227-96.772-63.5270.082-44.72-99.742-106.296-3.64268-80.843-12.288-43.95311-65.61-88.765
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating-580.3-765.5-174.8-198.8-1091.719.8-119.9-75.0172.49.3-59.01.118.4-117.8-160.75.157.3-14.3-73.780.8-85.2-117.0-116.269.05.5-91.7-239.896.6-189.844.0-149.5-99.40.1-68.7-147.5-155.9-5.399.3-112.3-16.7-59.815.1-86.1-112.4

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value4328075445381994-275.1-95.5238-71.873-113.6177-87.348-9.226-48.57947-36.43399122-134.841-60.399103119-164.733-96.441902156.6342649182-146.612-297.818238133-91.567535.36991-244.189-82.78518194
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of InterestAndDividendIncomeOperating350.6644.8407.2417.51548.1-208.1-68.2168.5-50.556.3-86.3146.5-77.345.2-8.5-44.754.8-48.9127.0163.6-187.4-83.4141.8168.5-236.3-140.2128.3308.510.341.676.9286.1-229.2-457.7353.3195.5-132.677.67.5124.2-332.0-112.1238.3119.4

Payments Of Dividends Common Stock

us-gaap:PaymentsOfDividendsCommonStock

us-gaap:PaymentsOfDividendsCommonStock


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value2525232121612020201816151515131310109.8379.8089.8489.869.0319.079.0749.1157.2767.2627.0527.0366.1446.1175.6480.0105.1585.1555.1354.8144.8124.8094.7984.7584.816
Percentage of PaymentsOfDividendsCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Payments For Repurchase Of Common Stock

us-gaap:PaymentsForRepurchaseOfCommonStock

us-gaap:PaymentsForRepurchaseOfCommonStock


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.05.437460.0320.00.00.12.40.00.10.00.90.410.0470.0320.8590.7350.0770.733250.0995.2840.0150.0030.9725.6053.1590.00.00.00.4480.0010.0050.0010.2560.0510.0040.0290.1640.00.0
Percentage of PaymentsForRepurchaseOfCommonStock0.0100.0100.0100.00.0100.00.00.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

Debt Instrument Interest Rate Stated Percentage

us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:ConsolidatedEntities, us-gaap:Range, us-gaap:DebtInstrument

us-gaap:DebtInstrumentInterestRateStatedPercentage

srt:Subsidiaries, srt:Maximum, fibk:NotePayableSixPointTwoFourPercent


Debt
Period End2020-12-312019-12-312018-12-31
Value3.250.06240.0624
Percentage of DebtInstrumentInterestRateStatedPercentage100.0100.0100.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations srt:Subsidiaries srt:Maximum fibk:NotePayableSixPointTwoFourPercent0.00.00.0

srt:Subsidiaries, srt:Minimum, fibk:NotePayableSixPointTwoFourPercent


Debt
Period End2020-12-312019-12-312018-12-31
Value1.00.010.01
Percentage of DebtInstrumentInterestRateStatedPercentage30.816.016.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations srt:Subsidiaries srt:Minimum fibk:NotePayableSixPointTwoFourPercent0.00.00.0

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value79318.0221200.0428180.0642260.0940840.01387400.01748000.02523600.03373700.03484900.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value14.4915.3315.6116.1316.7717.0617.0117.216.616.26
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Liabilities

us-gaap:DeferredTaxLiabilities

us-gaap:DeferredTaxLiabilities


Deferred
Period End2020-12-312019-12-312018-12-312017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-06-302013-12-312012-12-312011-12-31
Value27268.60.0126.8391416119.765133.0243.553483.427415149
Percentage of DeferredTaxLiabilities100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CapitalizationOfInternallyOriginatedMortgageServicingRightsNoncashSupplementalDisclosures

fibk:CapitalizationOfInternallyOriginatedMortgageServicingRightsNoncashSupplementalDisclosures


Capitalization
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
Value0.80.12.23.24.32.04.50.01.71.11.61.81.41.31.4631.41.21.5
Percentage of CapitalizationOfInternallyOriginatedMortgageServicingRightsNoncashSupplementalDisclosures100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:FeeIncomeonDerivatives us-gaap:HedgingDesignation

fibk:FeeIncomeonDerivatives

us-gaap:Nondesignated


Fee
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-30
Value100000.01100000.01300000.03700000.01700000.01000000.0700000.0500000.0500000.0800000.0400000.00400000.0500000.0162000.0321000.0-42000.00245000.0000
Percentage of FeeIncomeonDerivatives100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.00.00.00.0

fibk:ImpairmentofRealEstateandOtherAssetsPendingDisposal

fibk:ImpairmentofRealEstateandOtherAssetsPendingDisposal


Impairmentof
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
Value0100000.000200000.0300000.0100000.0300000.00100000.000
Percentage of ImpairmentofRealEstateandOtherAssetsPendingDisposal0.0100.00.00.0100.0100.0100.0100.00.0100.00.00.0

fibk:OtherRealEstateOwnedExpenseNetOfIncome

fibk:OtherRealEstateOwnedExpenseNetOfIncome


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0-100000.0-100000.00100000.0-500000.0-1700000.0-800000.0200000.0100000.00200000.0-100000.0200000.0239000.0242000.034000.0-48000.0-153000.08000.0140000.0-39000.0129000.0-720000.0-823000.0-61000.0-61000.0-58000.0-134000.0-19000.01292000.018000.0-915000.01896000.03877000.02612000.01806000.01105000.02021000.02878000.02042000.01711000.01541000.02608000.02980000.0
Percentage of OtherRealEstateOwnedExpenseNetOfIncome0.0100.0100.00.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:PaymentsForProceedsFromRecoveriesofLoansPreviouslyChargedoff

fibk:PaymentsForProceedsFromRecoveriesofLoansPreviouslyChargedoff


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value-3.7-2.0-1.6-1.8-1.8-1.5-1.5-2.9-7.01.721-2.4
Percentage of PaymentsForProceedsFromRecoveriesofLoansPreviouslyChargedoff100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:RealEstateAcquiredThroughForeclosureAdditions

fibk:RealEstateAcquiredThroughForeclosureAdditions


Real
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value0.00.30.12.00.30.90.10.74.98.41.53.26.31.12.2181.4191.3950.3682.3131.3160.7923.2270.180.9841.1393.2570.4010.3980.9843.4151.0381.9523.2245.3313.81619133.3852.883
Percentage of RealEstateAcquiredThroughForeclosureAdditions0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:RealEstateAcquiredThroughForeclosureDisposals

fibk:RealEstateAcquiredThroughForeclosureDisposals


Real
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
Value0.20.63.32.72.01.29.5100.7-1.44.41.32.40.22.3452.1230.5830.9121.7410.8971.5550.2071.9294.6534.51.5715.2061.8581.1432.3253.1756.197123.13710159.9155.7653.6314.1714.592
Percentage of RealEstateAcquiredThroughForeclosureDisposals100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:RealEstateAcquiredThroughForeclosureValuationAdjustments

fibk:RealEstateAcquiredThroughForeclosureValuationAdjustments


Real
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value0100000.000200000.0200000.0100000.0-300000.00100000.000238000.09000.047000.00586000.017000.073000.00106000.077000.010000.000259000.02305000.02310000.0569000.0578000.02457000.01963000.0
Percentage of RealEstateAcquiredThroughForeclosureValuationAdjustments0.0100.00.00.0100.0100.0100.0100.00.0100.00.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0

fibk:SharesRepurchasedDuringThePeriodAsPercentageOfSharesAuthorizedForRepurchasePercent

fibk:SharesRepurchasedDuringThePeriodAsPercentageOfSharesAuthorizedForRepurchasePercent


Shares
Period End2021-06-302021-03-312020-09-30
Value01.326.3
Percentage of SharesRepurchasedDuringThePeriodAsPercentageOfSharesAuthorizedForRepurchasePercent0.0100.0100.0

us-gaap:AcceleratedShareRepurchasesAdjustmentToRecordedAmount

us-gaap:AcceleratedShareRepurchasesAdjustmentToRecordedAmount


Accelerated
Period End2021-06-302021-03-312020-09-30
Value0.02.946
Percentage of AcceleratedShareRepurchasesAdjustmentToRecordedAmount0.0100.0100.0

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments


Accretion
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-10600000.0-7700000.0-5700000.0-4500000.0-3300000.0-2400000.0-2500000.0-2200000.0-2200000.0-2000000.0-2100000.0-2400000.0-2700000.0-2800000.0-3152000.0-2754000.0-2919000.0-2791000.0-3097000.0-3076000.0-3109000.0-3238000.0-3353000.0-4506000.0-3337000.0-3684000.0-3906000.0-3696000.0-3717000.0-3371000.0-3229000.0-3524000.0-3820000.0-4082000.0-3787000.0-2725000.0-2510000.0-2678000.0-2980000.0-2441000.0-2334000.0-2598000.0-2659000.0-1844000.0
Percentage of AccretionAmortizationOfDiscountsAndPremiumsInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllowanceForLoanAndLeaseLossesWriteOffs

us-gaap:AllowanceForLoanAndLeaseLossesWriteOffs


Allowance
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
Value4.84.95.86.44.14.67.34.75.66.04.64.85.0-5.27.2787.464.4893.8558.9853.1153.4414.3023.7214.5471.5081.8612.3046.2742.6262.7915.6834.9153.8956.021014269.087222016
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllowanceForLoanAndLeaseLossesWriteOffs us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

fibk:AgriculturalFinancingReceivable


Allowance
Period End2021-06-302020-12-312020-09-302020-06-302020-03-31
Value0.20.00.00.10.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs4.20.00.02.40.0

fibk:AgriculturePortfolioSegment


Allowance
Period End2021-06-302020-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value0.20.10.10.00.00.00.0410.0480.022-0.0050.00.1880.00.2210.00.00.00.00.00.00.0640.0010.00.00.0040.010.00.005
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs4.22.41.70.00.0-0.00.51.10.6-0.10.05.50.05.90.00.00.00.00.00.02.30.00.00.00.10.10.00.0

fibk:CommercialPurposesecuredby14Family


Allowance
Period End2021-06-302020-09-302020-06-302020-03-31
Value0.10.00.00.1
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs2.10.00.02.2

fibk:CommercialRealEstateConstruction


Allowance
Period End2021-06-302020-06-302020-03-31
Value0.10.00.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs2.10.00.0

fibk:CommercialRealEstateOwnerOccupied


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value2.20.10.10.20.10.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs45.82.01.73.12.40.0

fibk:CommercialandFloorPlans


Allowance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.31.83.30.60.8
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs6.236.751.614.617.4

fibk:ConsumerIndirectFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.81.30.89999999999999960.81.21.2
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs16.726.515.512.529.326.1

fibk:LandAcquisitionAndDevelopmentConstructionFinancingReceivable


Allowance
Period End2021-06-302020-12-312020-09-302020-06-302020-03-31
Value0.10.00.00.00.5
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs2.10.00.00.010.9

fibk:RealEstateFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value2.50.20.10.20.10.5
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs52.14.11.73.12.410.9

fibk:ResidentialRealEstateConstructionFinancingReceivable


Allowance
Period End2021-06-302020-06-302020-03-31
Value0.10.00.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs2.10.00.0

us-gaap:CommercialBorrower


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.10.20.10.40.30.2
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs2.14.11.76.27.34.3

us-gaap:CommercialPortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value0.52.03.43.70.91.10.81.10.9-1.72.6091.0490.7933.7530.5791.0180.4880.430.7910.0610.3740.0224.6780.5340.7962.5891.7030.5690.8111.9624.3353.18
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs10.440.858.657.822.023.913.322.918.032.735.023.420.641.818.629.611.311.617.44.020.11.074.620.328.545.634.614.613.519.129.311.9

us-gaap:CommercialRealEstatePortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value2.20.10.10.20.10.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs45.82.01.73.12.40.0

us-gaap:ConstructionLoans


Allowance
Period End2021-06-302020-12-312020-09-302020-06-302020-03-31
Value0.30.00.00.00.5
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs6.20.00.00.010.9

us-gaap:ConsumerLoan


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.40.80.81.11.01.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs8.316.313.817.224.421.7

us-gaap:ConsumerPortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value1.62.72.32.53.03.03.03.02.8-2.73.1152.4122.5962.8462.1571.7121.8922.0081.5370.8371.3011.671.4370.9340.8461.1681.0831.2991.0621.4581.341.21
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs33.355.139.739.173.265.250.062.556.051.941.853.767.331.769.249.844.054.033.855.569.972.522.935.630.320.622.033.417.614.29.04.5

us-gaap:CreditCardReceivables


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.40.60.60.60.80.8
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs8.312.210.39.419.517.4

us-gaap:HomeEquity


Allowance
Period End2021-06-302021-03-312020-06-302020-03-31
Value0.00.10.00.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs0.02.00.00.0

us-gaap:ResidentialRealEstate


Allowance
Period End2021-06-302021-03-312020-06-302020-03-31
Value0.00.10.00.0
Percentage of AllowanceForLoanAndLeaseLossesWriteOffs0.02.00.00.0

us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss us-gaap:FinancialInstrument

us-gaap:DebtAndEquitySecuritiesUnrealizedGainLoss

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-30
Value400000.0
Percentage of DebtAndEquitySecuritiesUnrealizedGainLoss100.0

us-gaap:DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense

us-gaap:DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense


Debt
Period End2021-06-07
Value672
Percentage of DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense100.0

us-gaap:DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-07
Value17
Percentage of DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense2.6

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Debt
Period End2021-06-07
Value654
Percentage of DebtSecuritiesAvailableForSaleTransferToHeldToMaturityAllowanceForCreditLossExpense97.4

us-gaap:DebtSecuritiesUnrealizedGainLoss us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesUnrealizedGainLoss

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Debt
Period End2021-06-30
Value24
Percentage of DebtSecuritiesUnrealizedGainLoss100.0

us-gaap:DefinedBenefitPlanActuarialGainLoss

us-gaap:DefinedBenefitPlanActuarialGainLoss


Defined
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value0-100000.0-200000.0-200000.0-300000.0-200000.0-200000.0-200000.0-100000.0-200000.0-200000.0-100000.0-174000.0-176000.0-176000.0-739000.03940000.015000.013000.015000.015000.015000.013000.015000.01628000.033000.035000.035000.035000.033000.035000.035000.0-179000.035000.035000.033000.031000.035000.035000.0
Percentage of DefinedBenefitPlanActuarialGainLoss0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet us-gaap:HedgingDesignation

us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet

us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2020-12-312020-09-302020-06-302019-06-302018-12-312018-09-302017-12-312017-09-302016-12-312016-09-30
Value-300000.00200000.00002228000.0-1128000.000
Percentage of DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet100.00.0100.00.00.00.0100.0100.00.00.0

us-gaap:DividendsCommonStockCash

us-gaap:DividendsCommonStockCash


Dividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value252518542121612020201816151515131310109.8379.8089.8489.869.0319.079.0749.1157.2767.2627.0527.0366.1446.117105.1585.1555.1354.8144.8124.8094.7984.7584.816
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DividendsCommonStockCash us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Dividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value25258572121-61.22020201816151515131310109.8379.8089.8489.869.0319.079.0749.1157.2767.2627.0527.0366.1446.117105.1585.1555.1354.8144.8124.8094.7984.7584.816
Percentage of DividendsCommonStockCash100.0100.046.2100.0100.0-100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EquipmentExpense

us-gaap:EquipmentExpense


Equipment
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
Value4.14.44.44.14.22.83.03.33.43.53.23.52.93.13.3043.1512.7392.2732.472.3982.462.2564.1793.8493.7033.7934.123.3383.1573.2013.1923.1473.1633.0523.3013.2313.1893.1383.1953.0183.1293.223.3263.4113.356
Percentage of EquipmentExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FederalDepositInsuranceCorporationPremiumExpense

us-gaap:FederalDepositInsuranceCorporationPremiumExpense


Federal
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
Value1.51.61.41.31.61.60.00.41.61.51.31.41.41.51.2781.6660.7860.8750.881.2121.1981.2581.2221.191.3041.1421.2271.1721.0931.1161.1191.2051.3561.3771.6521.6221.6011.5951.6071.6311.6292.4662.5842.3372.667
Percentage of FederalDepositInsuranceCorporationPremiumExpense100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FeesAndCommissionsMortgageBankingAndServicing

us-gaap:FeesAndCommissionsMortgageBankingAndServicing


Fees
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value9.6117.91414136.1108.45.45.66.77.25.46.48.27.6
Percentage of FeesAndCommissionsMortgageBankingAndServicing100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FinanceLeaseRightOfUseAssetAmortization

us-gaap:FinanceLeaseRightOfUseAssetAmortization


Finance
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value0.20.13.2-15.00.054
Percentage of FinanceLeaseRightOfUseAssetAmortization100.0100.0100.0100.00.0100.0

us-gaap:FinancingReceivableAccruedInterestWriteoff

us-gaap:FinancingReceivableAccruedInterestWriteoff


Financing
Period End2020-09-302020-06-302020-03-312019-06-302019-03-31
Value100000.00200000.0-200000.0600000.0
Percentage of FinancingReceivableAccruedInterestWriteoff100.00.0100.0100.0100.0

us-gaap:FinancingReceivableAllowanceForCreditLossesEffectOfChangeInMethod

us-gaap:FinancingReceivableAllowanceForCreditLossesEffectOfChangeInMethod


Financing
Period End2020-12-31
Value3.0
Percentage of FinancingReceivableAllowanceForCreditLossesEffectOfChangeInMethod100.0

us-gaap:FinancingReceivableAllowanceForCreditLossesRecovery

us-gaap:FinancingReceivableAllowanceForCreditLossesRecovery


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value3700000.02000000.01600000.01800000.01800000.01500000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery100.0100.0100.0100.0100.0100.0

us-gaap:FinancingReceivableAllowanceForCreditLossesRecovery us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

fibk:CommercialPurposesecuredby14Family


Financing
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value200000.0200000.0100000.0100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery5.410.05.65.60.0

fibk:CommercialRealEstateConstruction


Financing
Period End2021-06-302021-03-312020-06-302020-03-31
Value0100000.000
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery0.05.00.00.0

fibk:CommercialRealEstateNonOwnerOccupiedLoans


Financing
Period End2021-06-302020-09-302020-06-302020-03-31
Value100000.0100000.000
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery2.75.60.00.0

fibk:CommercialRealEstateOwnerOccupied


Financing
Period End2020-12-312020-09-302020-06-302020-03-31
Value0100000.0100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery0.05.65.60.0

fibk:CommercialandFloorPlans


Financing
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1700000.0400000.0200000.0400000.0400000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery45.920.011.122.226.7

fibk:ConsumerIndirectFinancingReceivable


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value800000.0600000.0300000.0700000.0400000.0700000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery21.630.018.838.922.246.7

fibk:LandAcquisitionAndDevelopmentConstructionFinancingReceivable


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value300000.0100000.0200000.0200000.000
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery8.15.012.511.10.00.0

fibk:RealEstateFinancingReceivable


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value500000.0300000.0400000.0400000.0300000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery13.515.025.022.216.70.0

fibk:ResidentialRealEstate14Family


Financing
Period End2020-12-312020-09-302020-06-302020-03-31
Value00100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery0.00.05.60.0

us-gaap:CommercialBorrower


Financing
Period End2021-06-302020-12-312020-09-302020-06-302020-03-31
Value100000.000100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery2.70.00.05.60.0

us-gaap:CommercialPortfolioSegment


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value2000000.0600000.0400000.0300000.0600000.0400000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery54.130.025.016.733.326.7

us-gaap:CommercialRealEstatePortfolioSegment


Financing
Period End2021-06-302020-12-312020-09-302020-06-302020-03-31
Value100000.00200000.0100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery2.70.011.15.60.0

us-gaap:ConstructionLoans


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value300000.0200000.0200000.0200000.000
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery8.110.012.511.10.00.0

us-gaap:ConsumerLoan


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value200000.0300000.0300000.0200000.0300000.0200000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery5.415.018.811.116.713.3

us-gaap:ConsumerPortfolioSegment


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value1200000.01100000.0800000.01100000.0900000.01100000.0
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery32.455.050.061.150.073.3

us-gaap:HomeEquity


Financing
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value100000.0100000.00100000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery2.75.00.05.60.0

us-gaap:ResidentialRealEstate


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value100000.0100000.0200000.00200000.00
Percentage of FinancingReceivableAllowanceForCreditLossesRecovery2.75.012.50.011.10.0

us-gaap:GainLossOnFairValueHedgesRecognizedInEarnings us-gaap:HedgingDesignation

us-gaap:GainLossOnFairValueHedgesRecognizedInEarnings

us-gaap:Nondesignated


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-30
Value200000.0300000.0-3200000.0-600000.0500000.04500000.0-1200000.0400000.0600000.0400000.0-500000.00100000.0-100000.0358000.0290000.0-109000.0752000.0523000.0695000.000
Percentage of GainLossOnFairValueHedgesRecognizedInEarnings100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

us-gaap:GainLossOnSaleOfDebtInvestments

us-gaap:GainLossOnSaleOfDebtInvestments


Gain
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-100000.0200000.0100000.0000100000.000-100000.0000-60000.0771000.05000.02000.018000.0225000.0108000.0-21000.062000.023000.046000.06000.0-19000.0-8000.017000.071000.0-25000.030000.0-12000.08000.053000.066000.0198000.031000.01488000.038000.016000.02000.062000.066000.015000.0
Percentage of GainLossOnSaleOfDebtInvestments100.0100.0100.00.00.00.0100.00.00.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnSaleOfInvestments

us-gaap:GainLossOnSaleOfInvestments


Gain
Period End2020-09-302020-06-302020-03-312019-06-302019-03-31
Value02000000.0-1000000.000
Percentage of GainLossOnSaleOfInvestments0.0100.0100.00.00.0

us-gaap:GainLossOnSaleOfLoansAndLeases

us-gaap:GainLossOnSaleOfLoansAndLeases


Gain
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
Value6.83.910.014159.19.49.27.24.7181.21.41.69.8215.4554.9914.907114.5825.9564.5885.3515.6386.4384.3214.5285.3464.2783.3234.1065.3927.0867.8988.9588.2256.4965.9275.7133.7462.7242.265.765.008
Percentage of GainLossOnSaleOfLoansAndLeases100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnSaleOfPropertyPlantEquipment

us-gaap:GainLossOnSaleOfPropertyPlantEquipment


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-06-302019-03-312018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0400000.0-200000.0-200000.00100000.00000-137000.076000.00-76000.0-129000.0-304000.0-46000.0-142000.0-91000.0-34000.0652000.0204000.01188000.0-11000.066000.013000.0-7000.0208000.0-4000.020000.0-66000.0-11000.0543000.0-42000.00-25000.00-3000.0-264000.0-102000.0
Percentage of GainLossOnSaleOfPropertyPlantEquipment0.0100.0100.0100.00.0100.00.00.00.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0

us-gaap:GainsLossesOnSalesOfOtherRealEstate

us-gaap:GainsLossesOnSalesOfOtherRealEstate


Gains
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
Value100000.0100000.0200000.0200000.0-100000.0600000.01900000.01200000.0100000.0400000.0400000.00400000.00-434000.0158000.0401000.0-184000.0232000.057000.0534000.0102000.0129000.01126000.0986000.0750000.01298000.0-215000.0331000.0435000.037000.0524000.01851000.0820000.0273000.0774000.068000.0-74000.019000.0113000.0264000.0156000.0
Percentage of GainsLossesOnSalesOfOtherRealEstate100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:HeldToMaturitySecuritiesTransferredSecurityUnrealizedGainLoss

us-gaap:HeldToMaturitySecuritiesTransferredSecurityUnrealizedGainLoss


Held
Period End2021-06-30
Value24
Percentage of HeldToMaturitySecuritiesTransferredSecurityUnrealizedGainLoss100.0

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities


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-2.6-10.6-4.215-5.56.0-17.5123.5-6.1-5.56.59.7-10.9-6.8254.512-18.686-1.484-4.695-4.97910-7.1285.652-5.3153.414-15.682126.109-1.094-3.6942.021.49-2.251-1.8617.7136.859-10.4031.7444.9831.871-4.9771.702-2.0285.498
Percentage of IncreaseDecreaseInAccountsPayableAndAccruedLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInAccruedInterestReceivableNet

us-gaap:IncreaseDecreaseInAccruedInterestReceivableNet


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
Value900000.0-1100000.0-5600000.0200000.010200000.0-400000.0-4300000.0900000.01500000.01600000.0-3100000.05100000.0400000.0900000.0-2590000.0-2814000.08118000.0-2140000.0-1150000.02484000.0541000.0-822000.0-3861000.02017000.01766000.0179000.0-3219000.02702000.0-638000.0685000.0-3934000.01112000.0-103000.0506000.0-4547000.02480000.0529000.0-1567000.0-3020000.01406000.01208000.0-1248000.0-3623000.0-1178000.0
Percentage of IncreaseDecreaseInAccruedInterestReceivableNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInDeposits

us-gaap:IncreaseDecreaseInDeposits


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
Value4718773345421775-98.4-136.1309-31.5134-164.9203-80.4911.402-86.53250-75.93147137-126.0151853167-163.758-38.05346265431.38725178-98.013-212.066204134-9.45583-24.34856-136.5195.4712399
Percentage of IncreaseDecreaseInDeposits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInInterestPayableNet

us-gaap:IncreaseDecreaseInInterestPayableNet


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-1900000.01100000.0-2300000.0-700000.0-1500000.0-1800000.0100000.0-100000.0-15700000.02200000.01300000.0200000.0600000.0100000.0-49000.0-3269000.04086000.0-590000.0-201000.0-41000.0463000.0224000.0-367000.0-172000.0253000.0-720000.0264000.0-331000.0363000.0-10000.0-404000.0-869000.0-197000.0-69000.0-204000.0-1509000.0-40000.0132000.0-663000.0-2926000.0-450000.0-1016000.0-2063000.0-5201000.0
Percentage of IncreaseDecreaseInInterestPayableNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherOperatingAssets

us-gaap:IncreaseDecreaseInOtherOperatingAssets


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
Value317.8-12.6-9.31434-8.915123.77.3-5.19.7-3.91.27931-24.538-1.693-0.43-11.9079.9844.567-1.1443.732-2.5963.635.371-0.3440.8461.0835.994-2.43-7.0680.0643.292-5.627-0.847-0.907-1.6470.621-3.633-7.828-0.184-3.339
Percentage of IncreaseDecreaseInOtherOperatingAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements

us-gaap:IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements


Incremental
Period End2020-12-312020-09-12
Value03000000.0
Percentage of IncrementalCommonSharesAttributableToAcceleratedShareRepurchaseAgreements0.0100.0

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements


Incremental
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
Value70228.0122190.06886.096983.078034.0146920.01131.0211160.0202910.0286900.059268.0385900.0363840.0410980.0-12221.0436470.0461480.0558650.019254.0390710.0376190.0394830.0-19309.0428870.0463560.0461960.032834.0548430.0531700.0622960.092941.0585280.0427780.0287970.024023.0130510.093278.0108770.0-13698.067404.0114720.0
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InformationTechnologyAndDataProcessing

us-gaap:InformationTechnologyAndDataProcessing


Information
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-09-302015-06-30
Value8.48.18.2999999999999978.48.37.88.47.98.17.97.86.87.17.07.2316.5696.05.35.6575.2114.84.8322.522.593
Percentage of InformationTechnologyAndDataProcessing100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestAndDividendIncomeOperating

us-gaap:InterestAndDividendIncomeOperating


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1231251331281281321401411421301311211131071081088574787471727370696870696462646363656768696972737373767879
Percentage of InterestAndDividendIncomeOperating100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestExpenseDeposits

us-gaap:InterestExpenseDeposits


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value2.22.32.93.44.57.39.7131412108.97.26.26.0416.1975.0114.1183.2273.0993.1083.2283.3183.2413.2393.3093.5413.4873.3273.4243.5863.8214.0384.3554.8515.4145.7796.2626.8547.9058.9039.871111214
Percentage of InterestExpenseDeposits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestExpenseJuniorSubordinatedDebentures

us-gaap:InterestExpenseJuniorSubordinatedDebentures


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value700000.0700000.0600000.0700000.0700000.01000000.01000000.01100000.01200000.01200000.01100000.01100000.01000000.0900000.0832000.0819000.0782000.0745000.0719000.0698000.0675000.0663000.0622000.0610000.0600000.0589000.0796000.0598000.0592000.0588000.0602000.0607000.0601000.0696000.01033000.01110000.01467000.01507000.01474000.01451000.01455000.01448000.01423000.01526000.01456000.0
Percentage of InterestExpenseJuniorSubordinatedDebentures100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestExpenseOtherLongTermDebt

us-gaap:InterestExpenseOtherLongTermDebt


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1500000.01500000.01600000.01700000.01000000.0300000.0300000.0300000.0400000.0300000.0-700000.0400000.0300000.0200000.0-5000.0608000.0481000.0453000.0458000.0457000.0451000.0449000.0704000.0544000.0538000.0515000.0585000.0482000.0476000.0473000.0486000.0487000.0483000.0480000.0486000.0502000.0495000.0498000.0493000.0498000.0495000.0489000.0493000.0512000.0509000.0
Percentage of InterestExpenseOtherLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase

us-gaap:InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value100000.0100000.0200000.0100000.0100000.0500000.0800000.01000000.01100000.01000000.0900000.0700000.0700000.0400000.0383000.0350000.0272000.0248000.0147000.0100000.092000.090000.069000.055000.053000.054000.056000.052000.063000.066000.062000.058000.074000.0100000.0127000.0144000.0152000.0156000.0150000.0137000.0171000.0237000.0247000.0209000.0229000.0
Percentage of InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestIncomeDomesticDeposits

us-gaap:InterestIncomeDomesticDeposits


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0.70.30.59999999999999950.50.52.54.55.75.03.64.42.82.02.12.2872.3141.3331.2120.8550.6070.4820.6450.5350.3420.2710.3890.5040.3740.2250.2310.2750.2070.2120.2980.3830.3360.2790.2370.2560.20.2270.3670.360.2520.257
Percentage of InterestIncomeDomesticDeposits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestIncomeExpenseAfterProvisionForLoanLoss

us-gaap:InterestIncomeExpenseAfterProvisionForLoanLoss


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value118125125117103941241221211121171081009797977667726865636565636365646163636158585251494949494746454543
Percentage of InterestIncomeExpenseAfterProvisionForLoanLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestIncomeSecuritiesTaxExempt

us-gaap:InterestIncomeSecuritiesTaxExempt


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1400000.01400000.01100000.0600000.0500000.0500000.0500000.0500000.0500000.0500000.0600000.0600000.0600000.0600000.0714000.0795000.0855000.0792000.0890000.0820000.0858000.0879000.0937000.0962000.01040000.01059000.01092000.01085000.01083000.01097000.01134000.01153000.01215000.01226000.01256000.01223000.01240000.01204000.01196000.01188000.01194000.01171000.01145000.01137000.01173000.0
Percentage of InterestIncomeSecuritiesTaxExempt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestIncomeSecuritiesTaxable

us-gaap:InterestIncomeSecuritiesTaxable


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value151515151517161515151413131312119.7838.7228.2627.8787.9828.0387.487.418.07.9717.6927.2597.3097.647.867.667.6718.0468.499.1949.4589.7051010109.9119.6651010
Percentage of InterestIncomeSecuritiesTaxable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions us-gaap:ProductOrService

us-gaap:InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions

us-gaap:InvestmentAdvisoryManagementAndAdministrativeService


Investment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value6.36.36.35.95.46.26.05.95.86.15.75.85.85.95.55.55.1
Percentage of InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LaborAndRelatedExpense

us-gaap:LaborAndRelatedExpense


Labor
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
Value413943464439384040364036343434342825362326242425262523252422242223232323212128262720292727
Percentage of LaborAndRelatedExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue

us-gaap:LifeInsuranceCorporateOrBankOwnedChangeInValue


Life
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value1400000.01200000.02000000.06300000.0-2200000.01500000.02500000.02800000.0700000.0700000.01400000.01500000.0800000.01300000.01622000.01188000.01441000.01146000.01046000.01160000.01128000.01143000.0-6237000.08365000.0384000.0920000.01060000.0816000.0872000.0852000.0474000.0-901000.0444000.0429000.0358000.0522000.0507000.0462000.0518000.0282000.0535000.0489000.0189000.0472000.0
Percentage of LifeInsuranceCorporateOrBankOwnedChangeInValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:MortgageServicingRightsMSRImpairmentRecovery

us-gaap:MortgageServicingRightsMSRImpairmentRecovery


Mortgage
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0-5900000.001500000.05500000.02900000.0000000-9000.0-12000.0-2000.0-70000.0-14000.0-16000.0-20000.015000.050000.0-76000.0-56000.0-15000.0-19000.0-61000.0-11000.0-45000.022000.0-62000.0-11000.0-48000.0-10000.055000.052000.0-868000.0427000.01168000.027000.0-347000.0-2999000.01991000.0271000.0
Percentage of MortgageServicingRightsMSRImpairmentRecovery0.0100.00.0100.0100.0100.00.00.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NoninterestExpense

us-gaap:NoninterestExpense


Noninterest
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
Value99989799951009099112939990848585948063776262606065615961645554575255565757575756555452545855
Percentage of NoninterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NoninterestIncome

us-gaap:NoninterestIncome


Noninterest
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
Value353833443943354039343436373537383729423137273030312731292624252729283030272626232120252421
Percentage of NoninterestIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:NoninterestIncomeOtherOperatingIncome

us-gaap:NoninterestIncomeOtherOperatingIncome


Noninterest
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
Value2.64.12.04.64.33.62.54.05.14.34.14.52.63.93.4022.9825.8052.0732.9792.2992.4571.4863.0371.7692.7993.1225.192.0791.9371.8892.2031.4162.2281.6781.4271.7251.522.0991.641.2851.831.9272.5912.0251.498
Percentage of NoninterestIncomeOtherOperatingIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OccupancyNet

us-gaap:OccupancyNet


Occupancy
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
Value7.17.37.27.26.87.37.17.17.17.06.66.56.06.36.3826.0595.184.7894.3534.4134.2844.6644.4454.4134.5294.4924.774.5344.2534.2394.2064.2924.0634.0263.9683.7934.0373.9883.8154.184.0134.2154.2073.9393.963
Percentage of OccupancyNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossAfterTax

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossAfterTax


Oci
Period End2021-06-30
Value-18500000.0
Percentage of OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossAfterTax100.0

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax


Oci
Period End2021-06-30
Value-24800000.0
Percentage of OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax100.0

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossTax

us-gaap:OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossTax


Oci
Period End2021-06-30
Value-6300000.0
Percentage of OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossTax100.0

us-gaap:OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal

us-gaap:OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal


Off
Period End2021-03-312020-09-302020-06-302020-03-31
Value-4.84.01929
Percentage of OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal100.0100.0100.0100.0

us-gaap:OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal us-gaap:CumulativeEffectPeriodOfAdoption

srt:CumulativeEffectPeriodOfAdoptionAdjustedBalance


Off
Period End2021-06-302021-03-312020-06-302020-03-31
Value0.00.3-0.20.2
Percentage of OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal0.0-6.2-1.00.7

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax


Other
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
Value0-100000.0-200000.0-100000.0-200000.0-200000.0-200000.0-200000.0-100000.0-200000.0-200000.00
Percentage of OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax


Other
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
Value000-100000.0-100000.0000000-100000.0
Percentage of OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax0.00.00.0100.0100.00.00.00.00.00.00.0100.0

us-gaap:OtherComprehensiveIncomeLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossBeforeTax


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
Value23-66.9-8.3-4.43439-3.43.9202720-6.0-3.5-23.3-21.744-1.8247.8039.125-27.947-2.6389.5966.917-8.30110-8.778118.402-3.2812.83414-13.3421.797-35.578-5.69-4.6490.9-2.0270.757-8.12.77821
Percentage of OtherComprehensiveIncomeLossBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value17-49.9-5.3-3.32528-2.42.9142014-4.4-2.6-17.2-12.951-0.9734.5895.535-16.95-1.65.8214.195-5.0356.586-5.3246.7135.096-1.991.7198.682-8.0931.09-21.579-3.451-2.820.546-1.230.46-5.0481.685120.273
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value17-49.9-5.3-3.32528-2.42.9142014-4.4-2.7-17.2-12.986-0.9734.5895.535-16.95-1.65.8214.195-5.0356.586-5.3246.7135.096-1.991.7198.682-8.0931.091-21.579-3.451-2.820.546-1.2290.46-5.0481.685120.273
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0103.8100.0100.3100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.1100.0100.0100.0100.099.9100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax


Other
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
Value0-100000.0-200000.0-200000.0-300000.0-200000.0-200000.0-200000.0-100000.0-200000.0-200000.0-100000.0
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax


Other
Period End2021-06-302020-12-312020-09-302019-12-312019-09-302018-12-312018-09-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value-100000.0200000.0100000.00100000.0-100000.00-78000.0771000.05000.02000.018000.0225000.0108000.0-21000.062000.023000.046000.06000.0-19000.0-8000.017000.071000.0-25000.030000.0-12000.08000.053000.066000.0198000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax100.0100.0100.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossTax

us-gaap:OtherComprehensiveIncomeLossTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value5.9-17.0-3.0-1.19.510-1.01.05.17.25.3-1.6-0.9-6.1-8.758-0.8513.2143.59-10.997-1.0383.7752.722-3.2664.273-3.4544.3553.306-1.2911.1155.633-5.2490.707-13.999-2.239-1.8290.354-0.7970.297-3.0521.0938.2710.177
Percentage of OtherComprehensiveIncomeLossTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-06-302018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-09-30
Value-800000.0-100000.000200000.0000-5000.0-658000.0-486000.049000.02287000.0512000.0-804000.0-2197000.0601000.0-436000.0000
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax100.0100.00.00.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax us-gaap:HedgingDesignation

us-gaap:DesignatedAsHedgingInstrument


Other
Period End2020-12-312020-09-302020-06-302019-06-302018-12-312018-09-302018-06-302017-12-312017-09-302017-06-30
Value-300000.00200000.00000-2200000.0700000.0500000.0
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax0.00.0100.00.00.00.00.044000.0-106.4-102.9

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-06-302018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-09-30
Value-600000.0-100000.000200000.0000-37000.0-351000.0-285000.030000.01421000.0317000.0-499000.0-1362000.0364000.0-264000.0000
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax100.0100.00.00.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax


Other
Period End2021-06-302020-06-302019-06-302018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-09-30
Value-200000.0000032000.0-307000.0-201000.019000.0866000.0195000.0-305000.0-835000.0237000.0-172000.0000
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax100.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.0

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value-0.8-66.8-8.1-4.23439-3.14.2203320-6.3-3.8-23.7-22.053-1.8128.0069.354-34.62-3.43108.613-6.40110-9.196107.303-3.3222.81614-13.4021.794-35.625-5.717-4.4730.931-1.8640.755-7.0322.781210.417
Percentage of OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value-0.6-49.8-5.2-3.12528-2.23.2152414-4.6-2.8-17.5-13.218-0.9674.7085.673-21.032-2.0716.0965.253-3.8816.583-5.5786.4344.429-2.0151.7088.704-8.1291.088-21.607-3.467-2.7130.565-1.1310.459-4.4091.68712
Percentage of OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax

us-gaap:OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value-0.2-17.0-2.9-1.19.510-0.91.05.18.85.3-1.7-1.0-6.2-8.835-0.8453.2983.681-13.588-1.3593.9473.36-2.524.272-3.6184.1742.874-1.3071.1085.647-5.2730.706-14.018-2.25-1.760.366-0.7330.296-2.6231.0948.263
Percentage of OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherLaborRelatedExpenses

us-gaap:OtherLaborRelatedExpenses


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value14161311101411111414121112117.949109.8119.6168.9088.618.0668.8027.5767.3128.077.786.8127.8417.1648.3137.2897.3287.5468.1756.1137.4476.8198.9666.876.0877.3357.499
Percentage of OtherLaborRelatedExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherNoninterestExpense

us-gaap:OtherNoninterestExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value151614151417151717151515161516141412131212111212131113121010119.43111101110131412111210121110
Percentage of OtherNoninterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForOriginationOfMortgageLoansHeldForSale

us-gaap:PaymentsForOriginationOfMortgageLoansHeldForSale


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value20215625539154621124529534412929355178204552235193330273195294322239269260151653362371
Percentage of PaymentsForOriginationOfMortgageLoansHeldForSale100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForProceedsFromOtherLoansAndLeases

us-gaap:PaymentsForProceedsFromOtherLoansAndLeases


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-23.760-338.71281118-7.1-54.62.91293.2-3.8671055378-17.58374-35.985-34.895431535.67776611702067-6.6691262830636122673139-10.027-50.27-5.74329-64.419-54.93-74.775
Percentage of PaymentsForProceedsFromOtherLoansAndLeases100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForProceedsFromProductiveAssets

us-gaap:PaymentsForProceedsFromProductiveAssets


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-0.20.5125.27.64.96.42.55.52.25.60.6-2.52.4-1.264.6893.0924.4566.7661.4752.231.4083.7292.75-0.8960.382-9.540.293.1673.1423.1640.6031.2360.652.4473.5065.0143.4532.0732.3693.0911.6390.2372.918
Percentage of PaymentsForProceedsFromProductiveAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value84137889551961041952944513316122090
Percentage of PaymentsToAcquireAvailableForSaleSecuritiesDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquireHeldToMaturitySecurities

us-gaap:PaymentsToAcquireHeldToMaturitySecurities


Payments
Period End2021-06-302021-03-312019-12-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value1978250.01.70.30.00.00.09.8452.0140.9340.0038.2875.0134.87161.1051511116.294.1410.02.4550.167.4086.3472425117.5927.224.1925.5661.868137.096
Percentage of PaymentsToAcquireHeldToMaturitySecurities100.0100.00.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromIssuanceOfCommonStock

us-gaap:ProceedsFromIssuanceOfCommonStock


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.00.40.30.10.10.60.10.20.30.4-0.10.20.90.80.4431.086-0.1821.0841.0261.9730.6880.9961.460.2390.770.92.0051.3671.0712.4761.1342.8812.6543.1450.5850.0630.1951.0680.1130.170.0650.0370.00.061
Percentage of ProceedsFromIssuanceOfCommonStock0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0

us-gaap:ProceedsFromIssuanceOfUnsecuredDebt

us-gaap:ProceedsFromIssuanceOfUnsecuredDebt


Proceeds
Period End2020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.00.10.00.00.10.00.10.10.02.6
Percentage of ProceedsFromIssuanceOfUnsecuredDebt0.0100.00.00.0100.00.0100.0100.00.0100.0

us-gaap:ProceedsFromLifeInsurancePolicies

us-gaap:ProceedsFromLifeInsurancePolicies


Proceeds
Period End2020-12-312019-12-31
Value600000.01600000.0
Percentage of ProceedsFromLifeInsurancePolicies100.0100.0

us-gaap:ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase

us-gaap:ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-13.9-38.827164142-83.560-49.8-16.3-39.876-5.98.0-9.27.67355-7.7985060-7.6810.876-45.11273-33.6127.072-40.17769-31.428-25.91331296.796-45.891-38.58444.812-35.065-25.1854040-101.916-83.1991642.112
Percentage of ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities

us-gaap:ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value24829332637532441529632519216412610411311410614995741622272701531981122419521515583160152115252201434281254282331276199136227251
Percentage of ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleAndMaturityOfHeldToMaturitySecurities

us-gaap:ProceedsFromSaleAndMaturityOfHeldToMaturitySecurities


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value469.33.2122.3222.43.818111223212221322022263230233725322218207.1622.1853.647102.2953.5123.1234.332.5462.1933.7423.5352.6852.723.6524.611
Percentage of ProceedsFromSaleAndMaturityOfHeldToMaturitySecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleOfMortgageLoansHeldForSale

us-gaap:ProceedsFromSaleOfMortgageLoansHeldForSale


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value21717729147048122426025732013251368160218-2.143514243235329338257199298318318228247273245157184679350389
Percentage of ProceedsFromSaleOfMortgageLoansHeldForSale100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans

us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.30.73.52.91.91.811110.81.84.81.32.70.31.7632.4380.9840.7281.9730.9542.0890.3092.0585.7795.4862.3216.5041.6431.4742.763.2126.721143.95711169.9835.6913.6494.2844.8033.164.6967.891
Percentage of ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets

us-gaap:ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets


Proceeds
Period End2020-09-302020-06-302020-03-312019-06-302019-03-31
Value002200000.000
Percentage of ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets0.00.0100.00.00.0

us-gaap:ProfessionalFees

us-gaap:ProfessionalFees


Professional
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
Value3.23.42.32.93.02.73.93.52.31.91.71.92.11.22.1351.8881.7951.0291.3551.1911.1361.3081.7271.9161.5141.3011.0011.2331.2781.371.3751.1351.1361.1271.0591.051.0020.9331.1760.9950.726
Percentage of ProfessionalFees100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProvisionForLoanAndLeaseLosses

us-gaap:ProvisionForLoanAndLeaseLosses


Provision
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
Value0.0-5.13.25.219293.82.63.83.71.62.02.92.13.5253.4432.3551.731.0782.3632.554.03.2891.0981.341.0950.1180.261-2.001-5.0-4.0-3.00.3750.58.09.5121113141515171819
Percentage of ProvisionForLoanAndLeaseLosses0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProvisionForLoanAndLeaseLosses us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

fibk:AgriculturalFinancingReceivable


Provision
Period End2021-06-302021-03-312020-06-302020-03-31
Value0.00.10.10.1
Percentage of ProvisionForLoanAndLeaseLosses0.0-2.00.50.3

fibk:AgriculturalRealEstateFinancingReceivable


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.20.10.20.50.3
Percentage of ProvisionForLoanAndLeaseLosses0.0-2.03.82.61.0

fibk:AgriculturePortfolioSegment


Provision
Period End2021-03-312020-06-302020-03-312019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value0.10.10.1-0.20.00.10.3-0.0170.335-0.577-0.0280.0550.1731.1620.018-0.1870.0090.0080.2850.0670.1580.0250.026-0.0790.027-0.023-0.331-0.285-0.069
Percentage of ProvisionForLoanAndLeaseLosses-2.00.50.3-5.40.03.414.3-0.514.2-33.4-2.62.36.829.10.5-17.00.70.7241.525.7-7.9-0.5-0.72.67.2-4.6-4.1-3.0-0.6

fibk:CommercialPurposesecuredby14Family


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.40.20.20.62.4
Percentage of ProvisionForLoanAndLeaseLosses0.0-3.93.83.18.3

fibk:CommercialRealEstateConstruction


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.90.20.80.22.1
Percentage of ProvisionForLoanAndLeaseLosses0.0-3.915.41.07.2

fibk:CommercialRealEstateMultifamily


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.20.82.30.40.5
Percentage of ProvisionForLoanAndLeaseLosses0.0-15.744.22.11.7

fibk:CommercialRealEstateNonOwnerOccupiedLoans


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.22.51.57.92.0
Percentage of ProvisionForLoanAndLeaseLosses0.0-49.028.840.56.9

fibk:CommercialRealEstateOwnerOccupied


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1.40.80.13.42.2
Percentage of ProvisionForLoanAndLeaseLosses0.0-15.71.917.47.6

fibk:CommercialandFloorPlans


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value3.41.81.27.713
Percentage of ProvisionForLoanAndLeaseLosses0.0-35.323.139.546.6

fibk:ConsumerIndirectFinancingReceivable


Provision
Period End2021-06-302020-09-302020-06-302020-03-31
Value0.20.70.53.9
Percentage of ProvisionForLoanAndLeaseLosses0.013.52.613.4

fibk:LandAcquisitionAndDevelopmentConstructionFinancingReceivable


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.40.20.50.10.1
Percentage of ProvisionForLoanAndLeaseLosses0.0-3.99.60.50.3

fibk:RealEstateFinancingReceivable


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value3.72.93.210.08.1
Percentage of ProvisionForLoanAndLeaseLosses0.0-56.961.551.327.9

fibk:ResidentialRealEstate14Family


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1.90.11.12.70.5
Percentage of ProvisionForLoanAndLeaseLosses0.0-2.021.213.81.7

fibk:ResidentialRealEstateConstructionFinancingReceivable


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.20.20.30.20.5
Percentage of ProvisionForLoanAndLeaseLosses0.0-3.95.81.01.7

us-gaap:CommercialBorrower


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.00.20.30.30.4
Percentage of ProvisionForLoanAndLeaseLosses0.0-3.95.81.51.4

us-gaap:CommercialPortfolioSegment


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value3.81.81.18.6163.60.50.7-0.71.530.453-4.128-0.3180.2654.313171.1562.0040.2240.993-0.2233.598-0.494-1.072-1.36-0.3770.7631.0210.3154.2220.866
Percentage of ProvisionForLoanAndLeaseLosses0.0-35.321.244.156.297.325.024.1-33.344.419.2-238.6-29.511.2169.1442.235.1182.516.790.7-189.01378.524.721.434.012.6203.5204.23.944.47.2

us-gaap:CommercialRealEstatePortfolioSegment


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1.02.53.9114.7
Percentage of ProvisionForLoanAndLeaseLosses0.0-49.075.060.016.2

us-gaap:ConstructionLoans


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.70.60.60.52.7
Percentage of ProvisionForLoanAndLeaseLosses0.0-11.811.52.69.3

us-gaap:ConsumerLoan


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.00.70.60.30.4
Percentage of ProvisionForLoanAndLeaseLosses0.0-13.711.51.51.4

us-gaap:ConsumerPortfolioSegment


Provision
Period End2021-06-302020-09-302020-06-302020-03-312019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value0.11.90.84.72.02.41.50.72.620.4892.0482.6462.3952.1231.2291.0420.430.6461.1251.1910.4230.346-0.5780.20.2890.5790.5371.5370.1920.784
Percentage of ProvisionForLoanAndLeaseLosses0.036.54.116.254.1120.051.733.376.120.8118.4245.5101.483.330.731.739.248.2102.71009.3162.1-17.311.6-5.0-9.6154.4107.419.22.06.5

us-gaap:CreditCardReceivables


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.30.70.60.00.4
Percentage of ProvisionForLoanAndLeaseLosses0.0-13.711.50.01.4

us-gaap:HomeEquity


Provision
Period End2021-06-302020-09-302020-06-302020-03-31
Value0.10.00.00.1
Percentage of ProvisionForLoanAndLeaseLosses0.00.00.00.3

us-gaap:ResidentialRealEstate


Provision
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value1.80.11.12.70.4
Percentage of ProvisionForLoanAndLeaseLosses0.0-2.021.213.81.4

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax


Reclassification
Period End2021-06-302020-09-302019-09-30
Value-100000.0100000.0100000.0
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax100.0100.0100.0

us-gaap:RepaymentsOfOtherLongTermDebt

us-gaap:RepaymentsOfOtherLongTermDebt


Repayments
Period End2020-09-302019-09-302017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.01.90.0350.0170.0170.0160.0170.0170.015151.2670.0150.0150.0130.0110.0120.0120.2110.0110.0110.010.010.0110.010.0090.2690.0110.0110.0110.0110.51
Percentage of RepaymentsOfOtherLongTermDebt0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised

us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised


Stock
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0400000.0100000.0100000.0600000.0200000.0300000.0400000.0-100000.0300000.0900000.0800000.0443000.0316000.0588000.01084000.01026000.01973000.0688000.0996000.01460000.0239000.0770000.0900000.01385000.01367000.01071000.02476000.01134000.02338000.02654000.03145000.0286000.063000.0195000.01068000.0113000.0170000.065000.037000.0-1000.061000.0
Percentage of StockIssuedDuringPeriodValueStockOptionsExercised0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised us-gaap:StatementEquityComponents

us-gaap:CommonStockIncludingAdditionalPaidInCapital


Stock
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0400000.0100000.0100000.0600000.0200000.0300000.0400000.0-100000.0300000.0900000.0800000.0443000.0316000.0588000.01084000.01026000.01973000.0688000.0996000.01460000.0239000.0770000.0900000.01385000.01367000.01071000.02476000.01134000.02338000.02654000.03145000.0286000.063000.0195000.01068000.0113000.0170000.065000.037000.0-1000.061000.0
Percentage of StockIssuedDuringPeriodValueStockOptionsExercised0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StockRepurchasedAndRetiredDuringPeriodShares us-gaap:StatementClassOfStock

us-gaap:StockRepurchasedAndRetiredDuringPeriodShares

us-gaap:CommonClassA


Stock
Period End2020-09-302020-06-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-02-282014-03-31
Value1.44530.00.00.00.00.00.00.00.00.00.00.00.00.0276350.9482420.00.20.00.5658750.00.036703-100.0295820.100355100
Percentage of StockRepurchasedAndRetiredDuringPeriodShares100.00.00.00.00.00.00.00.00.00.00.00.00.0100.0100.00.0100.00.0100.00.0100.0100.0100.0100.0

us-gaap:StockRepurchasedAndRetiredDuringPeriodValue

us-gaap:StockRepurchasedAndRetiredDuringPeriodValue


Stock
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
Value0.05.437460.0320.00.00.12.40.00.10.00.90.410.0470.0320.8590.7350.0770.733250.0995.2840.0150.0030.9725.6053.1590.00.00.00.4480.0010.0050.0010.2560.0510.0040.0290.1640.00.0
Percentage of StockRepurchasedAndRetiredDuringPeriodValue0.0100.0100.0100.00.0100.00.00.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

us-gaap:StockRepurchasedAndRetiredDuringPeriodValue us-gaap:StatementEquityComponents

us-gaap:CommonStockIncludingAdditionalPaidInCapital


Stock
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
Value0.05.437460.0320.00.00.12.40.00.10.00.90.410.0470.0320.8590.7350.0770.733250.0995.2840.0150.0030.9725.6053.1590.00.00.00.4480.0010.0050.0010.2560.0510.0040.0290.1640.00.0
Percentage of StockRepurchasedAndRetiredDuringPeriodValue0.0100.0100.0100.00.0100.00.00.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

us-gaap:TransferToOtherRealEstate

us-gaap:TransferToOtherRealEstate


Transfer
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
Value0.00.30.12.00.30.90.10.74.98.41.43.36.21.22.0371.6281.1860.3682.3131.3160.7923.2270.180.9841.1393.257
Percentage of TransferToOtherRealEstate0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TreasuryStockAcquiredAverageCostPerShare

us-gaap:TreasuryStockAcquiredAverageCostPerShare


Treasury
Period End2021-06-302021-03-312020-09-30
Value039.6932.05
Percentage of TreasuryStockAcquiredAverageCostPerShare0.0100.0100.0

us-gaap:UnrealizedGainLossOnDerivatives

us-gaap:UnrealizedGainLossOnDerivatives


Unrealized
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-06-302018-12-312018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value-800000.0-100000.000200000.000000-658000.0-486000.049000.02287000.0512000.0-804000.0-2197000.0601000.0-436000.00000
Percentage of UnrealizedGainLossOnDerivatives100.0100.00.00.0100.00.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.00.0

dei:EntityCommonStockSharesOutstanding us-gaap:StatementClassOfStock

dei:EntityCommonStockSharesOutstanding

us-gaap:CommonClassA


Entity
Period End2021-01-312020-06-302020-03-312020-01-312019-09-302019-06-302019-03-312019-01-312018-09-302018-06-302018-03-312018-01-312017-09-302017-06-302017-03-312017-01-312016-09-302016-06-302016-03-312016-01-312015-09-302015-06-302015-03-312015-01-312014-09-302014-06-302014-03-312014-01-312013-09-302013-06-302013-03-312013-01-312012-09-302012-06-302012-03-312012-01-312011-09-302011-06-30
Value4042424343423838383434333333212121212121212121212120201919181817171616161616
Percentage of EntityCommonStockSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CommonClassB


Entity
Period End2021-01-312020-06-302020-03-312020-01-312019-09-302019-06-302019-03-312019-01-312018-09-302018-06-302018-03-312018-01-312017-09-302017-06-302017-03-312017-01-312016-09-302016-06-302016-03-312016-01-312015-09-302015-06-302015-03-312015-01-312014-09-302014-06-302014-03-312014-01-312013-09-302013-06-302013-03-312013-01-312012-09-302012-06-302012-03-312012-01-312011-09-302011-06-30
Value2121222222222222222222222323232323232323232323232323242424242525262626262626
Percentage of EntityCommonStockSharesOutstanding51.651.652.051.251.652.058.258.859.066.066.468.269.169.7105.9106.8109.1111.7112.8110.3110.1109.5110.4108.7110.0118.3118.2121.7127.4131.3136.7144.9154.1155.9157.7161.1163.1165.0

fibk:AccruedInterestPayableFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

fibk:AccruedInterestPayableFairValueDisclosure

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value5.06.95.88.18.81012121210.07.86.76.3755.65.6488.9174.8315.4215.6225.6475.1844.965.3275.3665.1135.8335.5695.3164.9534.9635.3676.2366.502
Percentage of AccruedInterestPayableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:AccruedInterestPayableFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value5.06.95.88.18.81012121210.07.86.76.3755.65.6488.9174.8315.4215.6225.6475.1844.965.3275.3665.1135.8335.5695.3164.9534.9635.3676.2366.502
Percentage of AccruedInterestPayableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value5.06.95.88.18.81012121210.07.86.76.3755.65.6488.9174.8315.4215.6225.6475.1844.965.3275.3665.1135.8335.5695.3164.9534.9635.3676.2366.502
Percentage of AccruedInterestPayableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:AccruedInterestReceivableFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

fibk:AccruedInterestReceivableFairValueDisclosure

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value50505156564646515046444839383840352729312726273129272730262726302928
Percentage of AccruedInterestReceivableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:AccruedInterestReceivableFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value50505156564646515046444839383840352729312726273129272730262726302928
Percentage of AccruedInterestReceivableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Accrued
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value50505156564646515046444839383840352729312726273129272730262726302928
Percentage of AccruedInterestReceivableFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:AdvancestoSubsidiariesNet us-gaap:ConsolidatedEntities

fibk:AdvancestoSubsidiariesNet

srt:ParentCompany


Advancesto
Period End2020-12-312019-12-312018-12-312017-12-31
Value41484625
Percentage of AdvancestoSubsidiariesNet100.0100.0100.0100.0

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn


Capital
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value122111941165115211381121111311181110976
Percentage of CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn dei:LegalEntity

fibk:FirstInterstateBank


Capital
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value121711911162114811351118111011141108973
Percentage of CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn99.799.799.799.799.799.799.799.799.899.7

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets


Capital
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value10.510.50.1050.1050.1050.1050.1050.09875
Percentage of CapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule

fibk:CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value523511499493488480477479475445
Percentage of CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule dei:LegalEntity

fibk:FirstInterstateBank


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value521510498492486479475477474443
Percentage of CommonEquityTierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIPhaseInSchedule99.799.799.799.799.799.799.799.799.899.7

fibk:CommonEquityTierOneCapitalToBeWellCapitalized

fibk:CommonEquityTierOneCapitalToBeWellCapitalized


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value755739721713704694689692687642
Percentage of CommonEquityTierOneCapitalToBeWellCapitalized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneCapitalToBeWellCapitalized dei:LegalEntity

fibk:FirstInterstateBank


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value753737719711702692687689686640
Percentage of CommonEquityTierOneCapitalToBeWellCapitalized99.799.799.799.799.799.799.799.799.899.7

fibk:CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets

fibk:CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets


Common
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value6.56.50.0650.0650.0650.0650.0650.065
Percentage of CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets dei:LegalEntity

fibk:FirstInterstateBank


Common
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value6.56.50.0650.0650.0650.0650.0650.065
Percentage of CommonEquityTierOneCapitalToBeWellCapitalizedToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets

fibk:CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value11.4511.5111.5711.80.12070.12010.12620.12190.11940.114
Percentage of CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets dei:LegalEntity

fibk:FirstInterstateBank


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value11.611.7811.9311.930.120.11710.11810.11620.11560.1127
Percentage of CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets101.3102.3103.1101.199.497.593.695.396.898.9

fibk:CommonEquityTierOneRiskedBasedCapital

fibk:CommonEquityTierOneRiskedBasedCapital


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value1331130912841294130912831338129812621153112710961006978962949931800814797787768781763755738
Percentage of CommonEquityTierOneRiskedBasedCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CommonEquityTierOneRiskedBasedCapital dei:LegalEntity

fibk:FirstInterstateBank


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value13451336132013051297124712481233122011291111103410139979941022748785765817798799805788776770
Percentage of CommonEquityTierOneRiskedBasedCapital101.1102.1102.7100.899.197.293.395.096.797.998.694.3100.7101.9103.3107.780.498.194.0102.6101.5104.0103.1103.3102.8104.4

fibk:ContractualMaturitiesTimeDeposits100000OrMoreAfter4Years

fibk:ContractualMaturitiesTimeDeposits100000OrMoreAfter4Years


Contractual
Period End2020-12-31
Value10
Percentage of ContractualMaturitiesTimeDeposits100000OrMoreAfter4Years100.0

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter2years

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter2years


Contractual
Period End2020-12-31
Value7300000.0
Percentage of ContractualMaturitiesTimeDeposits100000orMoreafter2years100.0

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter3years

fibk:ContractualMaturitiesTimeDeposits100000orMoreafter3years


Contractual
Period End2020-12-31
Value4000000.0
Percentage of ContractualMaturitiesTimeDeposits100000orMoreafter3years100.0

fibk:ContractualMaturitiesTimeDepositsSixMonthsthroughTwelveMonths

fibk:ContractualMaturitiesTimeDepositsSixMonthsthroughTwelveMonths


Contractual
Period End2020-12-31
Value355
Percentage of ContractualMaturitiesTimeDepositsSixMonthsthroughTwelveMonths100.0

fibk:ContractualMaturitiesTimeDepositsThreeMonthsorLess

fibk:ContractualMaturitiesTimeDepositsThreeMonthsorLess


Contractual
Period End2020-12-31
Value271
Percentage of ContractualMaturitiesTimeDepositsThreeMonthsorLess100.0

fibk:ContractualMaturitiesTimeDepositsThreeMonthsthroughSixMonths

fibk:ContractualMaturitiesTimeDepositsThreeMonthsthroughSixMonths


Contractual
Period End2020-12-31
Value190
Percentage of ContractualMaturitiesTimeDepositsThreeMonthsthroughSixMonths100.0

fibk:CreditExtensionCommitments

fibk:CreditExtensionCommitments


Credit
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value252223022280217322282122280728352727262025152190221621792100225015961600160415971582140115919951495141514881346125912381225111011761.144695112010631.049796
Percentage of CreditExtensionCommitments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:CreditExtensionCommitments us-gaap:GuaranteeObligationsByNature

fibk:UnusedCreditCardLines


Credit
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value6816846826916921480764746749726701681656635618673550544545569562581545528501476490447413401382287362337301296285
Percentage of CreditExtensionCommitments27.029.729.931.831.169.827.226.327.527.727.931.129.629.129.429.934.534.134.035.635.541.534.353.133.533.733.033.332.832.431.225.930.829486.626.927.827220.6

us-gaap:FinancialStandbyLetterOfCredit


Credit
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value59615958555642525646454750505254505054515252595859586465595347707166686769
Percentage of CreditExtensionCommitments2.42.72.62.72.52.61.51.82.11.81.82.22.32.32.52.43.13.23.43.23.33.73.85.84.04.24.34.84.84.33.96.46.15827.16.26.36661.7

fibk:CreditExtensionCommitmentsBeyondOneYear us-gaap:GuaranteeObligationsByNature

fibk:CreditExtensionCommitmentsBeyondOneYear

fibk:UnusedCreditCardLines


Credit
Period End2020-12-312019-12-31
Value22801212
Percentage of CreditExtensionCommitmentsBeyondOneYear100.0100.0

fibk:DeferredTaxAssetsNonPerformingLoanInterest

fibk:DeferredTaxAssetsNonPerformingLoanInterest


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1200000.01000000.01200000.01100000.01200000.0
Percentage of DeferredTaxAssetsNonPerformingLoanInterest100.0100.0100.0100.0100.0

fibk:DeferredTaxAssetsRightofUseAsset

fibk:DeferredTaxAssetsRightofUseAsset


Deferred
Period End2020-12-312019-12-312018-12-31
Value9200000.09700000.00
Percentage of DeferredTaxAssetsRightofUseAsset100.0100.00.0

fibk:DeferredTaxLiabilitiesAgencyStockDividends

fibk:DeferredTaxLiabilitiesAgencyStockDividends


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value1200000.01200000.01500000.01600000.02287000.02442000.02407000.01965000.02060000.02079000.0
Percentage of DeferredTaxLiabilitiesAgencyStockDividends100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:DeferredTaxLiabilitiesDeferredLoanCosts

fibk:DeferredTaxLiabilitiesDeferredLoanCosts


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value4400000.02800000.02600000.01700000.03000000.0
Percentage of DeferredTaxLiabilitiesDeferredLoanCosts100.0100.0100.0100.0100.0

fibk:DeferredTaxLiabilityLeaseLiabilities

fibk:DeferredTaxLiabilityLeaseLiabilities


Deferred
Period End2020-12-312019-12-312018-12-31
Value9500000.09900000.00
Percentage of DeferredTaxLiabilityLeaseLiabilities100.0100.00.0

fibk:Deferredtaxassetloandiscount

fibk:Deferredtaxassetloandiscount


Deferredtaxassetloandiscount
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value4000000.07200000.08300000.06700000.03152000.04552000.0
Percentage of Deferredtaxassetloandiscount100.0100.0100.0100.0100.0100.0

fibk:DepositsExcludingTimeDepositsFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

fibk:DepositsExcludingTimeDepositsFairValueDisclosure

us-gaap:FairValueInputsLevel1, us-gaap:EstimateOfFairValueFairValueDisclosure


Deposits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value1455414057131581277012127102441021310264993194089363956088058891878387518817629963246235589460045975588556550.057670.00.00.00.00.00.00.0
Percentage of DepositsExcludingTimeDepositsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.00.00.00.00.00.00.0

fibk:DepositsExcludingTimeDepositsFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Deposits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value145541405713158127701212710244102131026499319408936395608805889187838751881762996324623558946004595758855655576357675705504349754943487046424854
Percentage of DepositsExcludingTimeDepositsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.7100.0100.00.0100.00.00.00.00.00.00.00.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Deposits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value145541405713158127701212710244102131026499319408936395608805889187838751881762996324623558946004597558855655576357675705504349754943487046424854
Percentage of DepositsExcludingTimeDepositsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.00.00.00.00.00.00.0

fibk:FDICDepositInsuranceLimit

fibk:FDICDepositInsuranceLimit


F
Period End2020-12-31
Value250
Percentage of FDICDepositInsuranceLimit100.0

fibk:FederalReserveBankUnrestrictedCashHeldCarryingValue

fibk:FederalReserveBankUnrestrictedCashHeldCarryingValue


Federal
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value1989769574552625636631392622329
Percentage of FederalReserveBankUnrestrictedCashHeldCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:FinancingReceivableCARESAct

fibk:FinancingReceivableCARESAct


Financing
Period End2020-12-31
Value296
Percentage of FinancingReceivableCARESAct100.0

fibk:FinancingReceivableModificationsRecordedInvestmentAccrualMethod

fibk:FinancingReceivableModificationsRecordedInvestmentAccrualMethod


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value2.23.13.23.23.45.05.55.55.75.85.65.97.26.9121014162217161215161516202023192121233531353537
Percentage of FinancingReceivableModificationsRecordedInvestmentAccrualMethod100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:FinancingReceivableModificationsRecordedInvestmentNonAccrual

fibk:FinancingReceivableModificationsRecordedInvestmentNonAccrual


Financing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value5.09.111161917191416161731272423384457
Percentage of FinancingReceivableModificationsRecordedInvestmentNonAccrual100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:ForeclosedResidentialRealEstateincludedinOtherRealEstateOwned

fibk:ForeclosedResidentialRealEstateincludedinOtherRealEstateOwned


Foreclosed
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value2300000.02200000.03100000.02300000.02700000.03500000.01700000.02000000.02700000.02282000.01686000.02644.0
Percentage of ForeclosedResidentialRealEstateincludedinOtherRealEstateOwned100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:ImpairedFinancingReceivableRelatedAllowancePartialLoanChargeOffs us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency

fibk:ImpairedFinancingReceivableRelatedAllowancePartialLoanChargeOffs

us-gaap:FairValueInputsLevel3, us-gaap:FairValueMeasurementsNonrecurring


Impaired
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value2.21.70.00.2107.86.55.46.65.911111010101110109.3911011118.1998.768.529.6921214-12.098-12.561-22.84822-26.162-25.188-34.205
Percentage of ImpairedFinancingReceivableRelatedAllowancePartialLoanChargeOffs100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis us-gaap:InvestmentType

fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis

fibk:CallableWithinOneYear


Investment
Period End2021-06-302021-03-312020-12-312020-09-30
Value151265282252
Percentage of InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis100.0100.0100.0100.0

fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveFairValue us-gaap:InvestmentType

fibk:InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveFairValue

fibk:CallableWithinOneYear


Investment
Period End2021-06-302021-03-312020-12-312020-09-30
Value149258281252
Percentage of InvestmentSecuritiesPrimarilyClassifiedAsAvailableForSaleDebtMaturitiesRollingYearTwoThroughFiveFairValue100.0100.0100.0100.0

fibk:LoansReceivableImpairedFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

fibk:LoansReceivableImpairedFairValueDisclosure

us-gaap:FairValueInputsLevel3, us-gaap:CarryingReportedAmountFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Loans
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value15201716125.94139383643525754586163656850424247705045576367807891107
Percentage of LoansReceivableImpairedFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueInputsLevel3, us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Loans
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value121714116.23.627272630242836363234343739392119202750353041464857536374
Percentage of LoansReceivableImpairedFairValueDisclosure81.586.084.071.249.661.066.869.667.40.066.466.068.762.459.658.957.259.260.357.842.345.348.958.570.869.167.773.673.671.271.267.769.369.6

fibk:LoansReceivableImpairedFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel3, us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring, fibk:LoansAndLeasesReceivableImpairedLoans


Loans
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value121714116.23.627272624
Percentage of LoansReceivableImpairedFairValueDisclosure81.586.084.071.249.661.066.869.667.466.4

fibk:LoansReceivableImpairedFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel3, us-gaap:FairValueMeasurementsNonrecurring, fibk:LoansAndLeasesReceivableImpairedLoans


Loans
Period End2020-12-312019-12-312018-12-31
Value142724
Percentage of LoansReceivableImpairedFairValueDisclosure84.066.166.4

fibk:LoansReceivableImpairedFairValueDisclosure us-gaap:FairValueByMeasurementFrequency

us-gaap:FairValueMeasurementsNonrecurring


Loans
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value2.813-12.222-25.772-21.804
Percentage of LoansReceivableImpairedFairValueDisclosure16.033.2-33.640.6-39.5-51.1

fibk:LongLivedAssetsToBeDisposedFairValueDisclosure us-gaap:DisposalGroupClassification, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

fibk:LongLivedAssetsToBeDisposedFairValueDisclosure

us-gaap:DisposalGroupHeldforsaleNotDiscontinuedOperations, us-gaap:FairValueInputsLevel3, us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value7300000.05000000.05300000.05000000.05000000.05000000.06200000.06900000.05000000.04900000.0
Percentage of LongLivedAssetsToBeDisposedFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:LongLivedAssetsToBeDisposedFairValueDisclosure us-gaap:DisposalGroupClassification, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency

us-gaap:DisposalGroupHeldforsaleNotDiscontinuedOperations, us-gaap:FairValueInputsLevel3, us-gaap:FairValueMeasurementsNonrecurring


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value7300000.05000000.05300000.05000000.05000000.05000000.06200000.06900000.05000000.04900000.0
Percentage of LongLivedAssetsToBeDisposedFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:LongLivedAssetsToBeDisposedFairValueDisclosure us-gaap:FairValueByMeasurementFrequency

us-gaap:FairValueMeasurementsNonrecurring


Long
Period End2020-12-312019-12-312018-12-31
Value200000.0200000.0500000.0
Percentage of LongLivedAssetsToBeDisposedFairValueDisclosure3.83.210.2

fibk:LongTermDebtAcquiredorAssumed us-gaap:ConsolidatedEntities, us-gaap:LongtermDebtType

fibk:LongTermDebtAcquiredorAssumed

srt:Subsidiaries, us-gaap:NotesPayableOtherPayables


Long
Period End2020-12-312019-12-312018-12-312017-12-31
Value12121114
Percentage of LongTermDebtAcquiredorAssumed100.0100.0100.0100.0

fibk:OtherLongTermDebtFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

fibk:OtherLongTermDebtFairValueDisclosure

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value121120116111110101011141313191515118.266282727272727274141383736353534343435
Percentage of OtherLongTermDebtFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:OtherLongTermDebtFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value112112112112112131313151515221515138.039282727272727274343433836363636373737
Percentage of OtherLongTermDebtFairValueDisclosure92.893.696.5100.7101.8132.4133.7123.0108.2113.7121.5114.398.799.4115.997.399.2101.7101.8100.5101.4100.9101.0103.0103.6113.1100.8101.0104.3104.8107.0107.0106.2105.9

us-gaap:EstimateOfFairValueFairValueDisclosure


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value121120116111110101011141313191515118.266282727272727274141383736353534343435
Percentage of OtherLongTermDebtFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:OwnershipPercentageInPartnership us-gaap:LeaseArrangementType

fibk:OwnershipPercentageInPartnership

fibk:RelatedParty


Ownership
Period End2020-12-31
Value50.0
Percentage of OwnershipPercentageInPartnership100.0

fibk:PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtCost

fibk:PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtCost


Pledged
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value2323213219432087140013251351128813181280
Percentage of PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:RealEstateAcquiredThroughForeclosureFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

fibk:RealEstateAcquiredThroughForeclosureFairValueDisclosure

us-gaap:FairValueInputsLevel3, us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring, fibk:LoansAndLeasesReceivableOtherRealEstateOwned


Real
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value1.11.42.32.22.92.10.6
Percentage of RealEstateAcquiredThroughForeclosureFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0

fibk:RealEstateAcquiredThroughForeclosureFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel3, us-gaap:FairValueMeasurementsNonrecurring, fibk:LoansAndLeasesReceivableOtherRealEstateOwned


Real
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value1.11.42.32.22.92.10.6
Percentage of RealEstateAcquiredThroughForeclosureFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0

fibk:ServicingAssetAsPercentageOfServicedLoansHeldInPortfolio us-gaap:FinancialInstrument

fibk:ServicingAssetAsPercentageOfServicedLoansHeldInPortfolio

fibk:MortgageLoans


Servicing
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value0.670.00810.00750.00680.00590.00540.00540.00560.00590.00640.0083
Percentage of ServicingAssetAsPercentageOfServicedLoansHeldInPortfolio100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:ServicingAssetAtAmortizedCostBeforeValuationReserve us-gaap:FinancialInstrument

fibk:ServicingAssetAtAmortizedCostBeforeValuationReserve

fibk:MortgageLoans


Servicing
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
Value343027241815141413131318
Percentage of ServicingAssetAtAmortizedCostBeforeValuationReserve100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value988966943932921908901905898778
Percentage of TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn dei:LegalEntity

fibk:FirstInterstateBank


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value985964940929919905898902897776
Percentage of TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn99.799.799.799.799.799.799.799.799.899.7

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets


Tier
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value8.58.50.0850.0850.0850.0850.0850.07875
Percentage of TierOneCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value814796777768759747742745740630
Percentage of TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn dei:LegalEntity

fibk:FirstInterstateBank


Tier
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value811794774765756745740742738628
Percentage of TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedIn99.799.799.799.799.799.799.799.799.899.7

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets

fibk:TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets


Tier
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value7.07.00.070.070.070.070.070.06375
Percentage of TierOneCommonEquityCapitalRequiredForCapitalAdequacyUnderBaselIIIFullyPhasedInToRiskWeightedAssets100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TimeDeposits250000orMore

fibk:TimeDeposits250000orMore


Time
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value193278221182208222228207
Percentage of TimeDeposits250000orMore100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TimeDepositsFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

fibk:TimeDepositsFairValueDisclosure

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Time
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value101110371061111512181324144615301551139312991269112111161137117211959921044109010851100113711541153121112441259114111661196124412961394
Percentage of TimeDepositsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TimeDepositsFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Time
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value1011103610581112121213201450153515581406131712851140113411511182120210001051109210861103113111501149120512381254113511591190123712871385
Percentage of TimeDepositsFairValueDisclosure100.099.999.899.799.699.7100.2100.3100.4100.9101.4101.3101.6101.6101.2100.8100.6100.8100.7100.2100.1100.299.599.799.699.599.599.699.599.499.599.499.399.4

us-gaap:EstimateOfFairValueFairValueDisclosure


Time
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value101110371061111512181324144615301551139312991269112111161137117211959921044109010851100113711541153121112441259114111661196124412961394
Percentage of TimeDepositsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

fibk:TimeDepositsObtainedCertificateOfDepositAccountRegistryService

fibk:TimeDepositsObtainedCertificateOfDepositAccountRegistryService


Time
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value971178794253840517298
Percentage of TimeDepositsObtainedCertificateOfDepositAccountRegistryService100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1321331441481331381291451491429499857586929643445559485348534966564243474544464840334342373538
Percentage of AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccruedInvestmentIncomeReceivable

us-gaap:AccruedInvestmentIncomeReceivable


Accrued
Period End2020-12-312020-09-302019-12-31
Value12109.8
Percentage of AccruedInvestmentIncomeReceivable100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax


Accumulated
Period End2020-12-312020-09-302020-06-302019-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-12-31
Value-200000.0-200000.0-200000.000001300000.00-434000.01590000.0-23000.0-1444000.0-1761000.0-1262000.0100000.0-436000.00
Percentage of AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax100.0100.0100.00.00.00.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedges


Accumulated
Period End2021-06-302021-03-31
Value-700000.0-100000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax0.00.0

us-gaap:AllowanceForDoubtfulAccountsReceivable

us-gaap:AllowanceForDoubtfulAccountsReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312011-03-31
Value135136144145146129737574727372144
Percentage of AllowanceForDoubtfulAccountsReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllowanceForDoubtfulAccountsReceivable us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable

fibk:AgriculturalFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value0.40.60.70.90.91.11.6
Percentage of AllowanceForDoubtfulAccountsReceivable0.30.40.50.60.60.92.2

fibk:AgriculturalRealEstateFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value3.02.82.72.93.12.60.5
Percentage of AllowanceForDoubtfulAccountsReceivable2.22.01.92.02.12.00.7

fibk:AgriculturePortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value0.40.60.70.90.91.11.6
Percentage of AllowanceForDoubtfulAccountsReceivable0.30.40.50.60.60.92.2

fibk:CommercialAndFloorPlans


Allowance
Period End2020-12-312020-09-30
Value3425
Percentage of AllowanceForDoubtfulAccountsReceivable23.717.5

fibk:CommercialPurposeSecuredBy14Family


Allowance
Period End2020-12-312020-09-30
Value4.75.9
Percentage of AllowanceForDoubtfulAccountsReceivable3.34.1

fibk:CommercialPurposesecuredby14Family


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value4.44.74.75.05.14.45.9
Percentage of AllowanceForDoubtfulAccountsReceivable3.23.43.33.43.53.48.1

fibk:CommercialRealEstateConstruction


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value8.07.27.37.16.36.12.7
Percentage of AllowanceForDoubtfulAccountsReceivable5.95.35.14.94.34.73.7

fibk:CommercialRealEstateMultifamily


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value111111108.58.10.7
Percentage of AllowanceForDoubtfulAccountsReceivable8.68.67.67.45.86.31.0

fibk:CommercialRealEstateNonOwnerOccupiedLoans


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value2223252523158.8
Percentage of AllowanceForDoubtfulAccountsReceivable16.916.817.717.316.212.212.1

fibk:CommercialRealEstateOwnerOccupied


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value16171819191510.0
Percentage of AllowanceForDoubtfulAccountsReceivable12.312.712.713.113.112.213.7

fibk:CommercialandFloorPlans


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value29313436413325
Percentage of AllowanceForDoubtfulAccountsReceivable21.422.723.725.228.125.934.9

fibk:ConsumerIndirectFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1516161716164.5
Percentage of AllowanceForDoubtfulAccountsReceivable11.711.711.611.711.212.96.2

fibk:LandAcquisitionAndDevelopmentConstructionFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1.01.21.31.21.51.41.9
Percentage of AllowanceForDoubtfulAccountsReceivable0.70.90.90.81.01.12.6

fibk:RealEstateFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value79778078756528
Percentage of AllowanceForDoubtfulAccountsReceivable58.656.955.854.051.550.339.6

fibk:ResidentialRealEstate14Family


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1311119.210121.8
Percentage of AllowanceForDoubtfulAccountsReceivable9.98.47.96.37.010.02.5

fibk:ResidentialRealEstateConstructionFinancingReceivable


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1.51.41.61.61.31.11.5
Percentage of AllowanceForDoubtfulAccountsReceivable1.11.01.11.10.90.92.1

us-gaap:CommercialBorrower


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value0.30.30.30.30.40.31.2
Percentage of AllowanceForDoubtfulAccountsReceivable0.20.20.20.20.30.21.6

us-gaap:CommercialPortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value33363942463832
Percentage of AllowanceForDoubtfulAccountsReceivable24.926.427.228.931.829.644.7

us-gaap:CommercialRealEstatePortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value51525455513919
Percentage of AllowanceForDoubtfulAccountsReceivable37.738.238.037.935.030.626.7

us-gaap:ConstructionLoans


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value109.8109.99.18.66.1
Percentage of AllowanceForDoubtfulAccountsReceivable7.77.27.16.86.26.78.4

us-gaap:ConsumerLoan


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value4.64.84.64.85.15.52.9
Percentage of AllowanceForDoubtfulAccountsReceivable3.43.53.23.33.54.34.0

us-gaap:ConsumerPortfolioSegment


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value2222232423249.9
Percentage of AllowanceForDoubtfulAccountsReceivable16.216.316.616.516.119.213.6

us-gaap:CreditCardReceivables


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1.61.52.62.22.02.62.5
Percentage of AllowanceForDoubtfulAccountsReceivable1.21.11.81.51.42.03.4

us-gaap:HomeEquity


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1.41.41.41.51.51.41.0
Percentage of AllowanceForDoubtfulAccountsReceivable1.01.01.01.01.01.11.4

us-gaap:HomeEquityLoan


Allowance
Period End2020-12-312020-09-30
Value1.41.0
Percentage of AllowanceForDoubtfulAccountsReceivable1.00.7

us-gaap:ResidentialRealEstate


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1412121011142.8
Percentage of AllowanceForDoubtfulAccountsReceivable10.99.48.97.48.111.13.8

us-gaap:AllowanceForDoubtfulAccountsReceivable us-gaap:FinancingReceivableRecordedInvestmentByClassOfFinancingReceivable, us-gaap:InitialApplicationPeriodCumulativeEffectTransition

fibk:AgriculturalFinancingReceivable, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-312020-03-312019-12-31
Value-0.60.6-0.6
Percentage of AllowanceForDoubtfulAccountsReceivable-0.40.5-0.8

fibk:CommercialAndFloorPlans, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-31
Value-5.1
Percentage of AllowanceForDoubtfulAccountsReceivable-3.5

fibk:CommercialPurposeSecuredBy14Family, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-31
Value-3.8
Percentage of AllowanceForDoubtfulAccountsReceivable-2.6

fibk:LandAcquisitionAndDevelopmentConstructionFinancingReceivable, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-312020-03-312019-12-31
Value-0.10.1-0.1
Percentage of AllowanceForDoubtfulAccountsReceivable-0.10.1-0.1

fibk:ResidentialRealEstateConstructionFinancingReceivable, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-312020-03-312019-12-31
Value-0.90.9-0.9
Percentage of AllowanceForDoubtfulAccountsReceivable-0.60.7-1.2

us-gaap:CommercialBorrower, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-312020-03-312019-12-31
Value-1.11.1-1.1
Percentage of AllowanceForDoubtfulAccountsReceivable-0.80.9-1.5

us-gaap:CommercialPortfolioSegment, us-gaap:CumulativeEffectAdjustmentConsolidationOfVariableInterestEntity


Allowance
Period End2020-12-312020-03-312019-12-31
Value-10.010.0-10.0
Percentage of AllowanceForDoubtfulAccountsReceivable-6.97.7-13.7

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent


Allowance
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value3400000.03400000.03700000.03400000.02300000.02100000.00
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent100.0100.0100.0100.0100.0100.00.0

us-gaap:AllowanceForNotesAndLoansReceivableNoncurrent

us-gaap:AllowanceForNotesAndLoansReceivableNoncurrent


Allowance
Period End2020-12-31
Value2900000.0
Percentage of AllowanceForNotesAndLoansReceivableNoncurrent100.0

us-gaap:AssetsFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

us-gaap:AssetsFairValueDisclosure

us-gaap:FairValueInputsLevel1, us-gaap:EstimateOfFairValueFairValueDisclosure


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value194821962276186014258691076126911289558229657127447598829198077827014766557807085066377980.00.00.00.00.00.00.0
Percentage of AssetsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value15588148991405813697135291217612185119981182211215112291109710205102251005799021002873647474750873217308724271537154719471157795699869876929688466587128
Percentage of AssetsFairValueDisclosure800.1678.5617.4736.2949.41400.91131.6945.01047.31174.21366.21150.01433.41374.01325.11121.61090.3911.5955.81070.51537.91114.9927.91010.01412.71128.0890.90.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel3, us-gaap:EstimateOfFairValueFairValueDisclosure


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value121714116.23.624272630242836363234343739392119204450353041464857536374
Percentage of AssetsFairValueDisclosure0.70.80.60.60.40.42.22.12.33.22.93.05.14.84.33.93.84.65.05.74.53.02.76.39.95.53.80.00.00.00.00.00.00.0

us-gaap:AssetsFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value174831701216223156451503812979132061325412942121661202512160111791121911078110651109183418370836779398018806179257716787279507814706570296985697067487169
Percentage of AssetsFairValueDisclosure897.3774.7712.6840.91055.31493.31226.41044.01146.51273.71462.91260.11570.11507.61459.61253.41205.91032.41070.41193.01667.71223.31033.01118.91523.81234.2995.40.00.00.00.00.00.00.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value175501711316349155691496013049132851329512977122011207512090109531100510848108191098382098295824978187983804379067710786779447837704570356987693867217203
Percentage of AssetsFairValueDisclosure900.7779.3718.1836.81049.81501.31233.81047.21149.61277.41469.11252.91538.41478.81429.41225.61194.11016.11060.81176.21642.41217.81030.61116.31522.61233.5994.70.00.00.00.00.00.00.0

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure

us-gaap:FairValueInputsLevel3, us-gaap:CarryingReportedAmountFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value7300000.05200000.05500000.05200000.05200000.05200000.06400000.07100000.06000000.05400000.04000000.04000000.0800000.0565000.0565000.0565000.02363000.02363000.02363000.02363000.02363000.03590000.01785000.01785000.01785000.01785000.01785000.01785000.01785000.02014000.02014000.0566000.0
Percentage of AssetsHeldForSaleLongLivedFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency

us-gaap:ChangeDuringPeriodFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Assets
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value200000.0200000.0200000.0200000.0200000.0200000.0200000.01000000.0500000.0500000.0500000.00209000.0209000.0209000.01028000.0857000.0857000.0857000.0857000.01507000.0702000.0702000.0702000.0
Percentage of AssetsHeldForSaleLongLivedFairValueDisclosure3.83.63.83.83.83.12.816.79.312.512.50.037.037.037.043.536.336.336.336.342.039.339.339.3

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsNonrecurring


Assets
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value5000000.05300000.05000000.05000000.05000000.06200000.06900000.05000000.04900000.03500000.03500000.0800000.0800000.0356000.0356000.0356000.01335000.01506000.01506000.01506000.01506000.02083000.01083000.01083000.01083000.0
Percentage of AssetsHeldForSaleLongLivedFairValueDisclosure96.296.496.296.296.296.997.283.390.787.587.50.0100.063.063.063.056.563.763.763.763.758.060.760.760.7

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value376281869063212319102.61.51.72.03.99.616118.7286.7822125161017111712121413
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value4.63.76.55.44.80.41.20.70.50.20.00.10.10.1
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax12.45.98.06.35.30.65.53.02.51.90.06.75.92.6

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.10.10.20.20.00.00.10.10.00.00.00.00.0
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax0.30.20.10.20.20.00.00.40.50.00.00.00.00.0

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2956697682601921179.42.51.41.63.8
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax79.590.484.889.291.196.490.390.989.387.996.293.394.197.4

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.40.41.01.01.11.00.10.30.50.30.10.00.00.0
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax1.10.61.21.21.21.60.51.32.52.83.80.00.00.0

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value2.51.84.82.71.90.90.81.01.00.8
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax6.82.95.93.12.11.43.74.35.17.5

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value28535.71.91.79.57.25.76.51737554946248.1197.89112200.5420.141.1883.7251.6366.7693.6838.996108.55937
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2.65.90.10.50.85.50.00.00.00.31.01.01.00.3
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax9.111.11.826.347.157.90.00.00.01.72.71.82.01.2

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.10.11.20.40.40.50.91.81.81.70.8
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax1.85.35.912.65.67.07.75.14.93.23.43.3

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value11202.50.50.72.76.04.54.71224373315
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax41.639.143.926.341.228.483.378.972.370.165.067.666.962.9

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value6.7112.00.60.00.10.80.81.34.01015138.0
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax23.422.235.131.60.01.111.114.020.022.627.527.427.732.7

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value7.2141.00.20.10.00.00.00.00.1
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax25.227.617.510.55.90.00.00.00.00.6

us-gaap:USTreasurySecurities


Available
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.20.00.00.00.00.00.00.00.00.00.0
Percentage of AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax0.70.00.00.00.00.00.00.00.00.00.0

us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis

us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value39494011393233693229294629452714259625792305221322262325222921102076166116241511148015481450152915871763170815841501190319711950193519871966194518811983
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis us-gaap:FinancialInstrument

us-gaap:CollateralizedLoanObligations


Available
Period End2021-06-30
Value187
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis4.7

us-gaap:CorporateDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value40134429529227121513496949292939388
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis10.28.67.58.78.47.34.63.53.63.64.04.24.23.9

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value166.5102031414754616672748091
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis0.40.20.30.61.01.41.62.02.42.63.13.43.64.1

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value20642866283025352528235623032046176117351566146214911474
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis52.371.572.075.278.380.078.275.467.967.368.066.167.066.1

us-gaap:OtherDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.21.01.22.03.26.16.81.72.04.22.53.0
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis0.00.00.00.10.10.20.30.10.10.20.10.1

us-gaap:ResidentialMortgageBackedSecurities


Available
Period End2021-06-302021-03-31
Value291235
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis7.45.9

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value333334332278264202367427583601569576557569
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis8.48.38.58.38.26.912.515.722.523.324.726.025.025.5

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value44945846223312211180778077
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis11.411.411.86.93.83.82.72.93.13.0

us-gaap:USTreasurySecurities


Available
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value4971.08.010179.07.09.04.02.63.01.93.2
Percentage of AvailableForSaleDebtSecuritiesAmortizedCostBasis12.60.00.20.30.60.30.30.30.20.10.10.10.1

us-gaap:AvailableForSaleSecuritiesAmortizedCost us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesAmortizedCost

fibk:MortgageBackedSecuritiesVariableRate


Available
Period End2020-12-312019-12-312018-12-312017-12-31
Value220298219247
Percentage of AvailableForSaleSecuritiesAmortizedCost100.0100.0100.0100.0

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312019-12-312018-12-31
Value3845115
Percentage of AvailableForSaleSecuritiesAmortizedCost17.515.452.6

us-gaap:AvailableForSaleSecuritiesAmortizedCost us-gaap:StatementGeographical, us-gaap:FinancialInstrument

fibk:IdahoMontanaOregonSouthDakotaWashingtonandWyoming, us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312019-12-312018-12-31
Value262866
Percentage of AvailableForSaleSecuritiesAmortizedCost11.89.430.4

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value0.20.20.22.81.81.92.68.014292319131.7370.430.5960.50.320.0990.3761.0581.445-4.829-3.442-7.407-9.813-8.228-9.769
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss us-gaap:FinancialInstrument

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.10.11.20.40.40.50.91.80.60.60.0
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss50.050.050.042.922.221.119.211.212.42.02.60.0

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.10.11.01.41.21.65.59.618159.2
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss50.050.050.035.777.863.261.568.866.262.466.466.7

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value5.71.91.79.57.25.76.51737554946248.1197.89112200.5420.141.1883.7251.636-6.769-3.683-8.996-10.45-8.559-37.397
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.50.85.50.31.01.01.00.3
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss1.826.347.157.91.72.71.82.01.2

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.10.11.20.40.40.50.91.81.81.70.8
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss1.85.35.912.65.67.07.75.14.93.23.43.3

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2.50.50.72.76.04.54.71224373315
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss43.926.341.228.483.378.972.370.165.067.666.962.9

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2020-12-312020-09-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2.00.60.10.80.81.34.01015138.0
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss35.131.61.111.114.020.022.627.527.427.732.7

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312020-09-302020-06-302019-03-31
Value1.00.20.10.1
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss17.510.55.90.6

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value85529121249611278968751570190219591978204717851061100210101079204403266393437345198157176661166131811841185548344156108333
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-03-312018-12-312018-09-302018-06-302017-12-31
Value2054461593676404051
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue2.418.622.032.22.34.02.12.12.9

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value4.31218404635486469727874
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue0.54.48.68.14.13.95.54.13.63.74.04.1

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value446991322778966395399861238130013211109
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue52.234.262.355.879.471.361.762.865.166.366.862.1

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2020-12-312020-09-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value23510219185221287466517546538551
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue27.535.14.016.424.732.829.727.227.927.230.9

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312020-09-302020-06-302019-03-31
Value148221516
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue17.37.87.11.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value5.51.71.56.75.43.83.99.722262627106.3827.46112190.2220.0410.8122.6670.191-1.94-0.241-1.589-0.637-0.331-27.628
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-03-312018-12-312018-09-302018-06-302017-12-31
Value0.10.50.84.90.00.20.91.00.3
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1.829.453.373.10.00.93.43.82.8

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2.40.40.61.74.63.33.16.91419176.2
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss43.623.540.025.485.286.879.571.164.273.667.457.9

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2020-12-312020-09-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value2.00.60.10.80.50.82.87.94.86.53.4
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss36.435.31.514.813.220.528.935.018.424.631.8

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312020-09-302020-06-302019-03-31
Value1.00.20.10.0
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss18.211.86.70.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value8382661752839255884678721123114012661399108089997097710638311265556132360100355131109717109211841184548344155108333
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-03-312018-12-312018-09-302018-06-302017-12-31
Value2054461190.024384051
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue2.520.326.742.30.02.23.43.24.7

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value43488113143740452299535735851905670
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue51.833.064.750.780.076.964.161.465.574.771.562.0

us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2020-12-312020-09-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value23510219185136168336363199266284
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue28.138.27.020.023.135.938.632.317.521.026.4

us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2020-12-312020-09-302020-06-302019-03-31
Value14822150.0
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue17.78.58.60.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value1624372132023084076977798197126487051613133151212961822113734194605855574492260.110.1120.1250.1370.1540.160.177
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue us-gaap:FinancialInstrument

us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value4.3121840463548646922240.0
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue25.952.748.718.723.011.511.89.28.92.83.40.0

us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value121119133155187240450503448415439
Percentage of AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue74.147.351.362.677.060.758.964.564.754.758.462.3

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value624977687652
Percentage of AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value723948991931
Percentage of AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value745846921642
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value671697658406
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value10621062736627
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value9351038996864
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value1516112415871446
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue


Available
Period End2021-06-302021-03-312020-12-312020-09-30
Value1626133513621251
Percentage of AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtSecurities

us-gaap:AvailableForSaleSecuritiesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value395740204008345333173000296027322609257222702158217822802208211120801657161115331505156314561545159217771711158615061893194719391923201119951979191319552016189618731786
Percentage of AvailableForSaleSecuritiesDebtSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtSecurities us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value3957402040083453331730002960273226092270
Percentage of AvailableForSaleSecuritiesDebtSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtSecurities us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:CollateralizedLoanObligations


Available
Period End2021-06-30
Value187
Percentage of AvailableForSaleSecuritiesDebtSecurities4.7

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:CorporateDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value403342302297275210135969591
Percentage of AvailableForSaleSecuritiesDebtSecurities10.28.57.58.68.37.04.63.53.64.0

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value176.61020314047546070
Percentage of AvailableForSaleSecuritiesDebtSecurities0.40.20.30.60.91.31.62.02.33.1

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value2082290128972611260924142317206317741544
Percentage of AvailableForSaleSecuritiesDebtSecurities52.672.272.375.678.780.578.375.568.068.0

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:OtherDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value0.21.01.22.03.26.16.82.0
Percentage of AvailableForSaleSecuritiesDebtSecurities0.00.00.00.10.10.20.30.1

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value326323331278265203366426582559
Percentage of AvailableForSaleSecuritiesDebtSecurities8.38.08.38.18.06.812.415.622.324.6

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value444445465236124112807881
Percentage of AvailableForSaleSecuritiesDebtSecurities11.211.111.66.83.73.72.72.93.1

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:USTreasurySecurities


Available
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value4961.08.010179.07.09.02.6
Percentage of AvailableForSaleSecuritiesDebtSecurities12.60.00.20.30.60.30.30.30.1

us-gaap:AvailableForSaleSecuritiesDebtSecurities us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value3957402040083453331730002960273226092270
Percentage of AvailableForSaleSecuritiesDebtSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value3957402040083453331730002960273226092270
Percentage of AvailableForSaleSecuritiesDebtSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AvailableForSaleSecuritiesDebtSecurities us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:FinancialInstrument

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:CollateralizedLoanObligations


Available
Period End2021-06-30
Value187
Percentage of AvailableForSaleSecuritiesDebtSecurities4.7

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:CorporateDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value403342302297275210135969591
Percentage of AvailableForSaleSecuritiesDebtSecurities10.28.57.58.68.37.04.63.53.64.0

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value176.61020314047546070
Percentage of AvailableForSaleSecuritiesDebtSecurities0.40.20.30.60.91.31.62.02.33.1

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprises


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value2082290128972611260924142317206317741544
Percentage of AvailableForSaleSecuritiesDebtSecurities52.672.272.375.678.780.578.375.568.068.0

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:OtherDebtSecurities


Available
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value0.21.01.22.03.26.16.82.0
Percentage of AvailableForSaleSecuritiesDebtSecurities0.00.00.00.10.10.20.30.1

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:USGovernmentAgenciesDebtSecurities


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value326323331278265203366426582559
Percentage of AvailableForSaleSecuritiesDebtSecurities8.38.08.38.18.06.812.415.622.324.6

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:USStatesAndPoliticalSubdivisions


Available
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value444445465236124112807881
Percentage of AvailableForSaleSecuritiesDebtSecurities11.211.111.66.83.73.72.72.93.1

us-gaap:EstimateOfFairValueFairValueDisclosure, us-gaap:FairValueMeasurementsRecurring, us-gaap:USTreasurySecurities


Available
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302018-12-31
Value4961.08.010179.07.09.02.6
Percentage of AvailableForSaleSecuritiesDebtSecurities12.60.00.20.30.60.30.30.30.1

us-gaap:AvailableForSaleSecuritiesDebtSecurities us-gaap:FinancialInstrument

us-gaap:Collateralized