GATX


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

Table of contents



us-gaap:CommonStockValue
us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents
us-gaap:SharesIssued
us-gaap:StatementEquityComponents
us-gaap:CommonStockSharesIssued

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare

us-gaap:AllocatedShareBasedCompensationExpense

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:IncomeLossFromContinuingOperations

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments

us-gaap:IncomeTaxExpenseBenefit
us-gaap:StatementEquityComponents

us-gaap:InterestExpense
us-gaap:StatementBusinessSegments

us-gaap:NetIncomeLoss

us-gaap:OperatingCostsAndExpenses
us-gaap:StatementBusinessSegments

us-gaap:OperatingExpenses

us-gaap:OtherNonoperatingIncomeExpense
us-gaap:StatementBusinessSegments

us-gaap:Revenues
us-gaap:StatementBusinessSegments

us-gaap:SellingGeneralAndAdministrativeExpense

us-gaap:Assets
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:Liabilities

us-gaap:LiabilitiesAndStockholdersEquity
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:StockholdersEquity
us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:StatementEquityComponents
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:AssetsCurrent
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:AssetsNoncurrent

us-gaap:PropertyPlantAndEquipmentGross

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:PropertyPlantAndEquipmentNet
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:InvestmentType

us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

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

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OtherAssets
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:LiabilitiesCurrent
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:LiabilitiesNoncurrent
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:LongTermDebt
us-gaap:LineOfCreditFacility
us-gaap:LongtermDebtType
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:DeferredIncomeTaxLiabilitiesNet
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:MinorityInterest

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OperatingLeaseLiability
gmt:OperatingLeasesByType

us-gaap:StockholdersEquity
us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:StatementEquityComponents

us-gaap:CommonStockValue
us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:TreasuryStockValue
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:MinorityInterest
us-gaap:StatementEquityComponents
us-gaap:StockIssuedDuringPeriodValueNewIssues
us-gaap:StatementEquityComponents
us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment
gmt:AssetAcquisition, us-gaap:StatementBusinessSegments

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:PaymentsOfDividends

us-gaap:EffectiveIncomeTaxRateContinuingOperations

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice

us-gaap:DeferredTaxLiabilities

us-gaap:ProceedsFromRepaymentsOfShortTermDebt

gmt:CashFlowHedgeGainLosstobeReclassifiedwithinTwelveMonthsGross

gmt:CostofRepairsandMaintenance
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
gmt:DisposalGroupIncludingDiscontinuedOperationExpense

gmt:DispositionGainsonOwnedAssets
us-gaap:StatementBusinessSegments
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
gmt:EquityMethodInvestment.SummarizedFinancialData.NetIncome
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
gmt:EquityMethodInvestmentSummarizedFinancialInformation.Revenue.
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
gmt:EquityMethodInvestmentSummarizedFinancialInformationExpenses
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
gmt:EquityMethodInvestmentSummarizedFinancialInformationGainsLosses

gmt:GainLossOnDispositionOfAssetsNet
us-gaap:StatementBusinessSegments

gmt:GatxOperatingLeaseOtherIncome

gmt:IncomeLossFromEquityMethodInvestmentBeforeTax
us-gaap:StatementBusinessSegments

gmt:MarineOperatingExpense
us-gaap:StatementBusinessSegments

gmt:MarineOperatingRevenue
us-gaap:StatementBusinessSegments

gmt:NonoperatingIncomeResidualSharingIncome
us-gaap:StatementBusinessSegments

gmt:NonremarketingDispositionGainLoss
us-gaap:StatementBusinessSegments

gmt:OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIbeforeTax
gmt:AssetAcquisition, us-gaap:RelatedPartyTransactionsByRelatedParty, us-gaap:StatementBusinessSegments
gmt:PaymentsForAssetAcquisition
gmt:AssetAcquisition, us-gaap:SubsequentEventType

gmt:PortfolioInvestmentsandCapitalAdditions
us-gaap:StatementBusinessSegments

gmt:PortfolioProceeds

gmt:PresentValueOfDividends

gmt:ProvisionForIncomeTaxesEquityMethodInvestment

gmt:SegmentProfitLoss
us-gaap:StatementBusinessSegments

gmt:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPaymentRate

us-gaap:CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths

us-gaap:CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations
us-gaap:DerivativeInstrumentRisk, us-gaap:IncomeStatementLocation
us-gaap:ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1
us-gaap:DerivativeInstrumentRisk, us-gaap:IncomeStatementLocation
us-gaap:ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1

us-gaap:CostOfPropertyRepairsAndMaintenance
us-gaap:StatementBusinessSegments
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanInterestCost
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanServiceCost

us-gaap:Depreciation

us-gaap:DepreciationNonproduction
us-gaap:StatementBusinessSegments
us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship, us-gaap:IncomeStatementLocation
us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
us-gaap:IncomeStatementLocation
us-gaap:DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet

us-gaap:DirectFinancingLeaseLeaseIncome

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerBasicShare

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DiscontinuedOperationTaxEffectOfDiscontinuedOperation
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationInterestExpense
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationOperatingExpense
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationOtherExpense
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations
us-gaap:DisposalGroupIncludingDiscontinuedOperationRevenue
us-gaap:StatementEquityComponents
us-gaap:DividendsCommonStockCash

us-gaap:EffectOfExchangeRateOnCashAndCashEquivalents

us-gaap:EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense

us-gaap:GainLossOnDispositionOfAssets

us-gaap:GainLossOnSalesOfAssetsAndAssetImpairmentCharges

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTax
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare

us-gaap:IncomeLossFromEquityMethodInvestments

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:LeaseIncome
us-gaap:StatementBusinessSegments

us-gaap:NetCashProvidedByUsedInDiscontinuedOperations

us-gaap:NetCashProvidedByUsedInFinancingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInInvestingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations

us-gaap:OperatingLeaseLeaseIncome

us-gaap:OperatingLeaseLeaseIncomeLeasePayments

us-gaap:OperatingLeaseVariableLeaseIncome

us-gaap:OperatingLeasesRentExpenseNet
us-gaap:StatementBusinessSegments

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax

us-gaap:OtherComprehensiveIncomeLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax
us-gaap:IncomeStatementLocation
us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship
us-gaap:OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax
us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship

us-gaap:OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax

us-gaap:OtherCostAndExpenseOperating
us-gaap:StatementBusinessSegments

us-gaap:OtherNoncashIncomeExpense

us-gaap:OtherOperatingIncome
us-gaap:StatementBusinessSegments

us-gaap:PaymentsForProceedsFromOtherInvestingActivities
us-gaap:BusinessAcquisition
us-gaap:PaymentsToAcquireBusinessesGross

us-gaap:ProceedsFromDivestitureOfBusinesses

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities

us-gaap:ProceedsFromSaleOfOtherProductiveAssets

us-gaap:RepaymentsOfLongTermCapitalLeaseObligations

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
us-gaap:StatementEquityComponents
us-gaap:StockIssuedDuringPeriodSharesNewIssues

dei:EntityCommonStockSharesOutstanding

dei:EntityPublicFloat

gmt:AmountOfSecuredDebtAvailableToBeBorrowedInAccordanceWithPublicDebtCovenants

gmt:AssetsOfContinuingOperations
us-gaap:StatementBusinessSegments
us-gaap:StatementGeographical

gmt:DebtAdjustmentForFairValueHedges

gmt:DeferredTaxAssetsOperatingLeaseLiability

gmt:DeferredTaxAssetsValuationOnStateNetOperatingLoss

gmt:DeferredTaxLiabilitiesRightofUseAssets
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation
gmt:DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees
us-gaap:RetirementPlanSponsorLocation
us-gaap:RetirementPlanType
gmt:DefinedBenefitPlanAmountsRecognizedinBalanceSheetandAccumulatedOtherComprehensiveIncomeLoss
gmt:DefinedBenefitPlans
gmt:DefinedBenefitPlanEstimatedFutureBenefitPayments

gmt:DefinedBenefitPlanPensionPlanswithAccumulatedBenefitObligationsinExcessofPlanAssetsAggregateProjectedFairValueofPlanAssets
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation
gmt:DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage
us-gaap:RetirementPlanSponsorLocation
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation
gmt:DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees
us-gaap:RetirementPlanSponsorLocation

gmt:DirectFinanceLeaseReceivablesNetOfDeferredIncome

gmt:LeaseLiability

gmt:LeaseRightofUseAsset

gmt:LeasesFutureMinimumPaymentsReceivable

gmt:LeasesFutureMinimumPaymentsReceivableCurrent

gmt:LeasesFutureMinimumPaymentsReceivableInFiveYears

gmt:LeasesFutureMinimumPaymentsReceivableInFourYears

gmt:LeasesFutureMinimumPaymentsReceivableInThreeYears

gmt:LeasesFutureMinimumPaymentsReceivableInTwoYears

gmt:LeasesFutureMinimumPaymentsReceivableThereafter

gmt:LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments
gmt:OperatingLeasesByType
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
gmt:NumberofAircraftEnginesUnderLeasingArrangement

gmt:OfficeFurnitureFixturesAndOtherEquipmentNet

gmt:OperatingandFinanceLeasesFutureMinimumPaymentsDueNextTwelveMonths

gmt:OtherAssetsCurrentAndNonCurrent
us-gaap:RetirementPlanType
gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossNetActuarialLossGainRecognized
us-gaap:RetirementPlanType
gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossPriorServiceCreditCostRecognized

gmt:RecourseDebt
us-gaap:FairValueByMeasurementBasis
gmt:RecourseFixedRateDebtFairValueDisclosure
us-gaap:FairValueByMeasurementBasis
gmt:RecourseFloatingRateDebtFairValueDisclosure

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:AccountsReceivableGrossCurrent

us-gaap:AccrualForEnvironmentalLossContingencies

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax
us-gaap:RetirementPlanType

us-gaap:AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:AssetsNet
us-gaap:BusinessAcquisition
us-gaap:BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
us-gaap:PropertyPlantAndEquipmentByType
us-gaap:CapitalLeasedAssetsGross

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivable

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableCurrent

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueInRollingYearThree

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueThereafter

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFiveYears

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFourYears

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInTwoYears

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassOtherPropertyPlantAndEquipmentNet

us-gaap:CommonStockCapitalSharesReservedForFutureIssuance
us-gaap:StatementClassOfStock

us-gaap:DebtInstrumentCarryingAmount
us-gaap:LongtermDebtType

us-gaap:DebtInstrumentUnamortizedDiscountPremiumNet

us-gaap:DebtLongtermAndShorttermCombinedAmount

us-gaap:DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsNet

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsDomestic

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsForeign

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsTaxCreditCarryforwardsForeign

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts

us-gaap:DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates

us-gaap:DeferredTaxLiabilitiesLeasingArrangements

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax

us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent
us-gaap:Range, us-gaap:PlanName, us-gaap:RetirementPlanSponsorLocation
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligation
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
gmt:DefinedBenefitPlans
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear

us-gaap:DefinedBenefitPlanFairValueOfPlanAssets
us-gaap:DefinedBenefitPlanByPlanAssetCategories
us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanWeightedAverageAssetAllocations

us-gaap:DerivativeAssets
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementFrequency
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation
us-gaap:DerivativeLiabilities
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementFrequency
us-gaap:FairValueByMeasurementFrequency
us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship, us-gaap:HedgingDesignation
us-gaap:DerivativeNotionalAmount

us-gaap:DirectFinancingLeaseDeferredSellingProfit

us-gaap:DirectFinancingLeaseLeaseReceivable

us-gaap:DirectFinancingLeaseNetInvestmentInLease

us-gaap:DirectFinancingLeaseUnguaranteedResidualAsset
us-gaap:AwardType
us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized

us-gaap:FinanceLeaseLiability

us-gaap:FinanceLeaseRightOfUseAsset

us-gaap:FinanceLeaseWeightedAverageDiscountRatePercent

us-gaap:GuaranteeObligationsMaximumExposure
us-gaap:DerivativeInstrumentRisk, us-gaap:GuaranteeObligationsByNature
us-gaap:GuaranteeObligationsByNature
us-gaap:BalanceSheetLocation
us-gaap:HedgedAssetFairValueHedgeCumulativeIncreaseDecrease
us-gaap:BalanceSheetLocation
us-gaap:HedgedLiabilityFairValueHedge
us-gaap:BalanceSheetLocation
us-gaap:HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease

us-gaap:LiabilityForAsbestosAndEnvironmentalClaimsNet
us-gaap:LineOfCreditFacility
us-gaap:LineOfCreditFacilityCapacityAvailableForTradePurchases
us-gaap:CreditFacility
us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity
us-gaap:LineOfCreditFacility

us-gaap:LitigationReserve

us-gaap:LoansAndLeasesReceivableAllowance

us-gaap:LoansAndLeasesReceivableNetReportedAmount

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:LongtermDebtType
us-gaap:LongTermDebtPercentageBearingFixedInterestRate
us-gaap:LongtermDebtType
us-gaap:LongTermDebtPercentageBearingVariableInterestRate
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:MinorityInterestOwnershipPercentageByParent

us-gaap:OperatingLeaseWeightedAverageDiscountRatePercent

us-gaap:OperatingLeasesFutureMinimumPaymentsDue
gmt:OperatingLeasesByType
gmt:OperatingLeasesByType
us-gaap:OperatingLeasesFutureMinimumPaymentsDueCurrent

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInFiveYears
gmt:OperatingLeasesByType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInFourYears
gmt:OperatingLeasesByType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInThreeYears
gmt:OperatingLeasesByType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueInTwoYears
gmt:OperatingLeasesByType

us-gaap:OperatingLeasesFutureMinimumPaymentsDueThereafter
gmt:OperatingLeasesByType

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivable
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableCurrent
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableInFourYears
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLeasesFutureMinimumPaymentsReceivableThereafter
dei:LegalEntity, us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:OperatingLossCarryforwards
us-gaap:IncomeTaxAuthority

us-gaap:OtherInventory

us-gaap:OtherLiabilities
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:OtherShortTermBorrowings

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent
us-gaap:RetirementPlanType

us-gaap:PrepaidExpenseCurrentAndNoncurrent

us-gaap:RestrictedCashAndCashEquivalents

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue

us-gaap:ShortTermDebtWeightedAverageInterestRate

us-gaap:TaxCreditCarryforwardValuationAllowance

Plots across concepts


IncomeStatement
Net Income Loss
Expenses
Other Nonoperating Income Expense
Balance Sheet
Goodwill
Assets
Derivative Assets
Current Assets
Accounts Receivable Gross Current
NonCurrent Assets
Goodwill
PropertyPlantAndEquipmentNet
Accumulated Depreciation Depletion And Amortization Property Plant And Equipment
Liabilities
Other Liabilities
Noncurrent Liabilities
Other Liabilities Noncurrent
Stockholders Equity
Accumulated Other Comprehensive Income Loss Net Of Tax
CashFlow
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInOperatingActivities
Net Income Loss
NetCashProvidedByUsedInInvestingActivities
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInFinancingActivities
Proceeds From Issuance Of Long Term Debt
Shares
Weighted Average Number Of Shares Outstanding Basic

Tables

  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:CommonStockValue █▇▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▅▄▄▄▄▄▄▄▄▄▄▄▄▃▃▃▃▃▂▂▂▂▂▂▁▁42.242.141.941.941.841.841.841.841.841.741.641.641.641.641.641.641.641.641.541.541.541.541.541.541.541.541.441.441.441.441.341.341.341.341.241.141.141.141.141.041.040.940.9NANANA
 us-gaap:CommonStockSharesIssued us-gaap:StatementEquityComponents us-gaap:CommonStock█▇▅▅▅▄▄▄▄▃▂▂▂▂▁68.268.167.867.767.767.667.567.567.567.467.367.367.367.267.1NANANA67.0NANANA66.8NANANA66.6NANANA66.3NANANA66.0NANANA65.8NANANA65.5NANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding █▁36.035.9NA35.435.435.4NA36.036.737.1NA38.538.438.5NA39.239.539.9NA40.641.141.8NA43.444.244.8NA45.246.346.8NA46.847.147.7NA47.647.547.5NA47.247.247.0NA46.746.747.5
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic █▁35.435.2NA35.034.934.9NA35.436.036.5NA37.737.737.9NA38.639.039.4NA40.140.641.4NA42.843.544.1NA44.445.546.0NA46.246.546.9NA46.946.846.7NA46.546.446.3NA46.246.246.0
us-gaap:EarningsPerShareBasic ▁▂▁▂▂▂▂▂▂▂▂▂▂▂█▂▂▂▁▃▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▂▁▁▁▁▁▁▁▁▁▁0.161.040.511.371.121.331.621.281.891.141.321.251.032.028.981.271.371.460.782.391.511.671.380.921.041.411.321.161.170.921.161.160.750.580.631.150.50.650.680.710.570.430.420.450.470.41
us-gaap:EarningsPerShareDiluted ▁▂▁▂▂▂▂▂▂▂▂▂▂▂█▂▂▂▂▃▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▂▁▁▁▁▁▁▁▁▁▁0.151.020.51.351.111.311.591.251.861.121.31.221.011.988.831.251.351.440.772.361.491.661.370.911.031.391.31.141.150.91.141.150.740.570.621.130.490.640.670.70.560.420.420.450.460.4
us-gaap:IncomeLossFromContinuingOperationsPerBasicShare ▁▅▃▇▅▆▆▅█▅1.6e-071.04e-065.1e-071.38e-061.06e-061.35e-061.21e-061.0500000000000001e-061.68e-061.13e-06NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare ▁▅▃▇▅▇▆▅█▅1.5e-071.02e-065e-071.3600000000000001e-061.0500000000000001e-061.33e-061.18e-061.03e-061.6499999999999999e-061.1100000000000002e-06NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AllocatedShareBasedCompensationExpense ▄▇▇▄▄▁▆▄▅▆▄▇▅▅▄▃▄▃█▃▂▂▂▂▃▂▅▃▃▃▃▃▃▃▃▂▂▃▄▁▂▂3.96.06.13.93.72.25.64.14.55.13.95.74.74.93.73.43.93.26.73.22.93.02.72.83.22.94.73.13.13.13.63.13.23.23.13.03.03.14.12.02.42.5NANANANA
us-gaap:ComprehensiveIncomeNetOfTax ▂▂▂▃▃▂▃▂▃▂▂▃▂▃█▃▃▃▂▃▂▃▂▂▃▂▂▂▃▂▄▄▂▂▂▃▂▃▁▁▂▃▂▃▁23.53.040.570.258.58.282.011.982.336.042.449.2-7.591.6361.966.597.677.510.9102.537.294.241.340.959.013.7-4.75.553.844.7113.2104.939.413.727.766.28.259.7-19.6-23.844.850.323.965.7-40.2NA
us-gaap:IncomeLossFromContinuingOperations ▁▅▃▆▅▆▆▅█▆5.536.517.848.237.047.242.137.260.341.2NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments ▄▃▂▃▂▃▃▃▅▃▂▃▃▆▂▄▄▅▁█▅▆▅▄▄▅▄▄▄▃▄▄▂▂▂▂▃▃50.737.717.837.223.939.736.244.267.535.229.348.334.982.624.857.263.069.49.7121.681.592.673.958.557.280.765.158.861.046.352.050.130.726.233.232.540.138.0NANANANANANANANA
us-gaap:IncomeTaxExpenseBenefit ▇▇▇▇▇▇▇▇▇▇▇▇▇█▁███▇██████████▇▇█▇▇▇▇▇▇▇▇▇▇▇▇▇▇13.68.47.711.84.712.912.511.915.68.4-8.713.19.120.6-304.020.419.320.6-2.941.126.730.842.820.320.827.021.519.920.214.117.631.39.17.5-0.2-2.215.313.211.410.89.35.9-1.97.23.77.6
us-gaap:InterestExpense ▇█▆▆▆▅▅▅▅▅▄▄▃▂▃▃▃▂▂▁▁▁▂▂▂▃▂▂▂▃▃▃▄▃▂▄▃▄▃▃▄▄▃▃▃▄50.053.648.848.647.446.846.746.347.146.543.942.642.239.941.140.240.039.238.236.236.537.238.037.738.540.938.838.139.542.041.441.143.240.939.542.941.642.642.040.943.142.942.041.341.242.6
us-gaap:NetIncomeLoss ▁▂▁▂▂▂▂▂▂▂▂▂▂▂█▂▂▂▂▃▂▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▁▂▂▂▁▁▁▁▁▁5.536.517.847.939.346.356.645.168.041.549.247.038.876.3342.149.053.457.530.995.761.269.358.239.545.462.258.551.353.142.153.353.835.127.129.753.823.530.331.632.926.419.919.521.121.518.7
us-gaap:OperatingCostsAndExpenses ▃▃▃▃▃▃▄▄▄▃▃▃▃▃▃▃▃▃▄▃▄▃▄▄▄▃▄▄▄▃▄▄▄▃█▂▂▁▂▂▂▁195.2188.6185.1184.3188.8199.2233.7229.1232.0194.9223.3218.8222.5192.7225.4226.7223.2188.2233.6224.0233.0185.7234.3238.0232.1193.7264.2257.7243.7180.3240.7239.1235.7178.8498.8136.0130.478.7137.5127.2122.890.1NANANANA
us-gaap:OperatingExpenses ▃▃▃▃▃▃▄▄▄▃▄▃▃▃▄▄▃▃▄▄▄▃▄▄▄▃▄▄▄▃▄▄▄▃█▂▂▁▂▂▂▁243.0235.7231.3226.3232.2241.6286.7273.5277.1241.0276.8265.3268.7237.6278.1269.5266.3231.1280.5272.1273.9224.5292.0282.4276.7239.4320.0303.5288.6223.0289.2281.1281.5220.8543.4174.6169.3116.8180.5165.7160.2126.5NANANANA
us-gaap:OtherNonoperatingIncomeExpense ▂▅▅▅▄▂▅▅▆▄▃▄▁▅▃▅▅▅▁█▄▄▄▄▅▄▅▄▃▄▆▄▄▅▄▄▆▆-8.1-1.3-0.8-1.2-3.0-8.2-2.3-1.8-0.6-3.2-6.7-3.8-9.8-1.3-6.6-2.1-1.1-1.3-8.94.3-3.9-3.3-4.5-3.1-1.6-4.0-2.1-3.1-4.9-3.40.2-4.4-3.1-1.1-4.2-3.90.5-0.6NANANANANANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments gmt:OtherBusinessSegments▁▇█▇▇▆▆▇▇▇▃▅▆▇▄▆█▇▅█▆██▇█▆██▆▇███▇████-7.3-0.50.2-0.6-1.0-1.7-2.0-0.6-0.4-0.2-5.4-2.7-1.2-0.2-4.4-1.50.4-0.1-2.80.3-1.30.20.1-0.10.5-1.80.00.2-1.7-0.30.40.50.2-0.20.30.30.20.2NANANANANANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments gmt:RailInternational0.2NA0.70.5-0.7-5.51.7-0.11.9-2.30.30.2-7.3-0.2-0.90.3-1.1-1.5-1.25.5-1.3-2.2-3.0-1.8-1.20.00.7-1.1-2.70.0-0.6-1.00.00.5-2.8-1.80.3-1.8NANANANANANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments gmt:RailNorthAmerica▆▇▅▆▆▇▅▆▅▇▅▆▆▆▅▆▆▅█▆▆▆▆▆▇▅▄▆▇▃▆▁▃▇▆▅▇▅-1.0-0.8-1.7-1.1-1.3-0.8-1.7-1.0-1.9-0.7-1.9-1.2-1.2-0.9-1.8-0.9-1.2-2.00.2-1.4-1.1-1.3-1.0-1.2-0.8-2.2-2.5-1.0-0.3-3.4-0.9-4.8-3.3-0.8-1.2-1.8-0.2-1.9NANANANANANANANA
us-gaap:Revenues ▄▃▃▃▃▃▆▆▆▄▆▅▅▃▆▆▅▄▆▆▆▅▇▇▆▄██▆▂▆▆▅▁▄▅▅▂▄▅▄▁▃▃▂▁317.1305.8304.9304.4300.5308.9356.7360.7359.4317.0356.4349.7349.5305.3352.8359.6348.4316.1362.1362.9358.9334.4378.7386.2365.3319.7401.4397.2365.8286.6356.6353.2338.9272.3331.7343.4343.0284.5330.0337.9314.6265.0306.3308.7288.2263.6
us-gaap:SellingGeneralAndAdministrativeExpense ▅▅▅▄▄▄▇▅▅▅▇▅▅▅▇▄▄▄▅▅▄▃█▅▅▅█▅▅▄▆▄▅▄▅▃▃▃▄▃▃▂▃▁▁▂47.847.146.242.043.442.453.044.445.146.153.546.546.244.952.742.843.142.946.948.140.938.857.744.444.645.755.845.844.942.748.542.045.842.044.638.638.938.143.038.537.436.437.531.032.833.5
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:Assets ▇█▆▆▆▆▅▅▆▅▄▄▄▄▄▄▄▄▄▄▄▄▃▃▃▄▃▃▃▄▃▂▂▂▂▂▂▂▂▁▁▁▁9400.59915.38937.68690.38512.78717.98285.18090.98353.18240.27616.77517.47495.57468.07422.47261.97272.17096.97105.47089.37090.67062.06894.26904.76860.07056.46937.56816.36921.17119.06549.66339.16119.26144.76055.46125.15917.95792.95857.55756.55642.55498.75442.4NANANA
us-gaap:Liabilities ▇█▆▆▅▆▅▅▅▅▄▄▄▄▄▄▄▄▄▄▄▄▃▄▃▄▃▃▃▄▃▂▂▂▂▂▂▂▂▂▁▁▁7429.17955.36980.26760.36637.46886.96450.06304.46518.36431.05828.65679.45677.95628.35629.75791.75829.15711.75758.25717.85782.15756.75614.05635.75574.65773.95623.55485.15546.75695.85152.65027.04900.14921.24811.24899.74747.24617.44730.24601.24451.44345.04328.7NANANA
us-gaap:LiabilitiesAndStockholdersEquity ▇█▆▆▆▆▅▅▆▅▄▄▄▄▄▄▄▄▄▄▄▄▃▃▃▄▃▃▃▄▃▂▂▂▂▂▂▂▂▁▁▁▁9400.59915.38937.68690.38512.78717.98285.18090.98353.18240.27616.77517.47495.57468.07422.47261.97272.17096.97105.47089.37090.67062.06894.26904.76860.07056.46937.56816.36921.17119.06549.66339.16119.26144.76055.46125.15917.95792.95857.55756.55642.55498.75442.4NANANA
us-gaap:StockholdersEquity ████▇▇▇▆▇▇▇▇▇▇▇▄▄▃▃▃▃▃▂▂▂▂▃▃▃▄▃▃▂▂▂▂▁▂▁▁▂▁▁1971.41960.01957.41930.01875.31831.01835.11786.51834.81809.21788.11838.01817.61839.71792.71470.21443.01385.21347.21371.51308.51305.31280.21269.01285.41282.51314.01331.21374.41423.21397.01312.11219.11223.51244.21225.41170.71175.51127.31155.31191.11153.71113.7NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:AssetsCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA352.7NANANA203.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:AssetsCurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName,us-gaap:EquityMethodInvestmentNonconsolidatedInvestee gmt:RrpfJointVentures,us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA352.7NANANA202.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CashAndCashEquivalentsAtCarryingValue ▄█▃▄▅▅▂▁▃▃▂▃▃▃▃▂▃▂▃▂▂▂▂▂▁▃▂▁▂▄▄▂▂▃▃▄▃▂▃▂▁▁▁▁▁▂417.9958.9292.2459.8492.9570.7151.048.6286.6248.4100.2254.5237.4233.1296.5199.2284.3155.2307.5211.5177.6216.2202.4116.058.6351.4209.959.4110.3447.0379.7150.796.7321.1234.2430.6227.7141.0248.4115.050.253.978.523.629.3173.8
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents ▄█▃▄▄▅▂▁▃▃▁▃▂▂▃▂▃▂▃▂418.1959.1292.6459.8492.9570.7151.048.6286.9254.6106.7258.6241.1237.4299.7202.9288.0159.0311.1215.9NANA219.7NANANA224.4NANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:AssetsNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA4766.9NANANA5015.9NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:PropertyPlantAndEquipmentGross ██▇▇▆▆▆▆▆▆▆▅▅▅▅▅▄▄▄▄▄▄▃▃▄▃▃▃▃▃▂▂▂▁▁10923.410835.010484.010070.29784.19972.59897.49759.89728.99587.99565.29262.99206.79191.89045.48915.98801.48631.18446.48545.48508.58440.48204.08141.28341.38194.28143.58110.18091.47958.77390.77400.67198.36918.26855.2NANANA6416.0NANANANANANANA
us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment ███▇▇▇▇▇▇▆▆▆▆▆▅▅▅▄▄▄▄▄▃▃▃▃▃▃▃▃▂▂▂▂▂▂▁▁▁▁▁▁▁3340.73311.83313.33226.03155.73222.13190.23152.13122.63062.03015.72965.02911.82897.72853.32814.62743.32666.12641.72633.42580.32563.92505.62487.92506.92434.92455.52425.52402.72358.92320.42291.92239.82224.72200.82149.82107.42107.52056.72061.22080.92086.72049.7NANANA
us-gaap:PropertyPlantAndEquipmentNet ██▇▇▆▆▆▆▆▆▆▅▅▅▅▅▅▅▄▅▅▅▄▄▄▄▄▄▄▄▃▃▃▂▂▂▂▂▁▁▁▁▁7582.77523.27170.76844.26628.46750.46707.26607.76606.36525.96549.56297.96294.96294.16192.16101.36058.15965.05804.75912.05928.25876.55698.45653.35834.45759.35688.05684.65688.75599.85070.35108.74958.54693.54654.44508.84508.14460.64359.34338.04261.74189.74133.8NANANA
us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures ▇███▇▆▆▆▅▅▄▅▄▄▄▄▃▂▂▂▁▁▁▁▂▁▁▁▁▁▁▁▃▅▅▆▆▆▆▇▇▆▅561.4592.2584.7582.5551.4532.4512.6506.7495.8480.0464.5478.5468.9455.9441.0449.3407.8396.9387.0376.8361.1356.3348.5364.1368.7359.7357.7348.1356.7348.5354.3361.9424.3485.5502.0532.3519.5509.1513.8547.5567.6524.6486.1NANANA
us-gaap:Goodwill █▇█▂▁▁▁▁▁▁▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▂▂▃▃▃▃▂▂▂▂▂▃▂▃▃▃▃140.3139.0143.784.281.780.681.579.982.481.682.983.684.087.385.684.682.678.778.081.781.082.479.781.481.279.186.188.894.394.794.693.590.889.891.790.089.092.590.592.798.596.792.7NANANA
us-gaap:OperatingLeaseRightOfUseAsset ▅▆▆▇▇▇▇███▁286.3326.5335.9364.3372.1402.8413.9430.1440.6449.50.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:LiabilitiesCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA311.0NANANA525.5NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LiabilitiesCurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName,us-gaap:EquityMethodInvestmentNonconsolidatedInvestee gmt:RrpfJointVentures,us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA200.6NANANA429.3NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:LiabilitiesNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA3674.7NANANA3703.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LiabilitiesNoncurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName,us-gaap:EquityMethodInvestmentNonconsolidatedInvestee gmt:RrpfJointVentures,us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA3243.6NANANA3367.5NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LongTermDebt NANA5358.5NANANA4813.9NANANA4473.1NANANA4412.6NANANA4286.2NANANA4205.4NANANA4203.8NANANA3838.5NANANA3283.0NANANA3504.2NANANA3019.0NANANA
 us-gaap:LongTermDebt us-gaap:LineOfCreditFacility us-gaap:ForeignLineOfCreditNANA580.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:LongtermDebtType gmt:RecourseFloatingRateDebtUnsecuredOneNANA300.0NANANA300.0NANANA300.0NANANA200.0NANANA0.0NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName gmt:RrpfJointVenturesNANA3454.7NANANA3811.7NANANA3469.3NANANA2753.8NANANA2449.7NANANA2387.1NANANA2289.9NANANA2023.4NANANA1996.9NANANANANANANANANANANA
us-gaap:DeferredIncomeTaxLiabilitiesNet █▇▇▄▁▃▂971.2960.4962.8936.4915.7930.2924.3NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:MinorityInterest us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName,us-gaap:EquityMethodInvestmentNonconsolidatedInvestee gmt:RrpfJointVentures,us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA1133.9NANANA989.4NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesNoncurrent NANA43.0NANANA33.9NANANA43.3NANANA29.1NANANA42.0NANANA33.5NANANA36.6NANANA31.6NANANA32.6NANANA33.8NANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:StockholdersEquity ████▇▇▇▆▇▇▇▇▇▇▇▄▄▃▃▃▃▃▂▂▂▂▃▃▃▄▃▃▂▂▂▂▁▂▁▁▂▁▁1971.41960.01957.41930.01875.31831.01835.11786.51834.81809.21788.11838.01817.61839.71792.71470.21443.01385.21347.21371.51308.51305.31280.21269.01285.41282.51314.01331.21374.41423.21397.01312.11219.11223.51244.21225.41170.71175.51127.31155.31191.11153.71113.7NANANA
us-gaap:CommonStockValue █▇▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▅▄▄▄▄▄▄▄▄▄▄▄▄▃▃▃▃▃▂▂▂▂▂▂▁▁42.242.141.941.941.841.841.841.841.841.741.641.641.641.641.641.641.641.641.541.541.541.541.541.541.541.541.441.441.441.441.341.341.341.341.241.141.141.141.141.041.040.940.9NANANA
us-gaap:AdditionalPaidInCapital ██▇▆▆▆▆▆▆▅▅▅▅▅▅▅▅▄▄▄▄▄▄▄▄▃▃▃▃▃▃▃▃▃▃▂▂▂▂▂▂▁▁759.4753.1735.4730.8728.8725.4720.1716.6713.0709.5706.4703.6702.7699.9698.0695.8693.1690.7687.8681.5679.2676.8677.4676.4673.8671.2672.8670.1667.5666.2668.9663.7660.6657.5658.5652.7649.5647.6644.4638.9636.7630.0626.2NANANA
us-gaap:RetainedEarningsAccumulatedDeficit ███████▇▇▇▇▇▆▆▆▅▄▄▄▄▄▄▃▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁2687.32700.32682.12682.02651.72630.02601.32561.52533.52482.62419.22387.02357.32335.92261.71936.21904.21868.01828.01813.61734.71689.91639.01597.51574.91547.21501.71458.41422.31384.61358.41320.01281.21261.31249.41234.51195.41186.81171.21153.61134.91122.71116.9NANANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▃▃▄▃▂▁▃▂▃▃▃▃▃▅▅▄▄▂▁▂▂▃▂▂▂▂▄▆███▅▃▃▄▄▃▄▃▅▇▆▅-153.0-171.0-137.5-160.2-182.5-201.7-163.6-189.0-155.8-170.1-164.6-157.8-160.0-113.7-109.6-129.4-146.9-191.1-211.1-191.1-197.9-173.9-198.8-181.9-183.3-196.9-148.4-85.2-39.4-40.1-42.7-102.6-153.7-158.0-144.6-142.6-155.0-139.7-169.1-117.9-61.2-79.6-110.0NANANA
us-gaap:TreasuryStockValue ████████▇▇▇▆▆▆▆▅▅▅▅▅▄▄▄▄▃▃▃▃▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁1364.51364.51364.51364.51364.51364.51364.51344.41297.71254.51214.51136.41124.01124.01099.01074.01049.01024.0999.0974.0949.0929.0878.9864.5821.5780.5753.5753.5717.4628.9628.9610.3610.3578.6560.3560.3560.3560.3560.3560.3560.3560.3560.3NANANA
 us-gaap:MinorityInterest us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName,us-gaap:EquityMethodInvestmentNonconsolidatedInvestee gmt:RrpfJointVentures,us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA1133.9NANANA989.4NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents us-gaap:CommonStock▄█▁▄▁▁▁▁▄▄▁▁▁▁0.10.20.00.10.00.00.00.00.10.10.00.00.00.0NANANANANANANANANANANA0.1NANANANANANANANANANANANANANANANANANANANA
 us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital▃█▃▁▂▃▂▂▂▂▂▁▂▁6.317.74.62.03.45.33.53.63.53.12.80.92.81.9NANANANANANANANANANANA4.6NANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities NANA134.7102.8146.353.0165.5121.3111.564.3167.2134.6129.577.2179.393.3172.252.0193.1194.1161.477.5222.3120.5135.755.8163.9117.2116.751.4147.7124.1104.724.2145.6112.384.128.2119.071.479.636.891.564.686.3-0.3
us-gaap:NetCashProvidedByUsedInInvestingActivities NANA-402.5-214.5-163.8-124.1-122.7-135.2-83.2-98.6-361.8-80.7-150.6-83.0-122.0-136.4-13.2-156.7-120.47.5-156.8-125.2-14.0-73.2-134.0-86.4-118.1-116.1-127.4-516.93.1-115.1-205.9-85.3-180.5-19.7-99.9-43.5-83.2-157.6-139.9-77.3-329.1-16.1-39.7-32.8
us-gaap:NetCashProvidedByUsedInFinancingActivities NANA99.775.8-313.5493.658.9-222.83.3182.542.5-35.928.7-56.738.6-42.2-31.6-48.724.3-167.9-41.860.5-121.210.7-295.6177.1106.6-50.1-326.1531.877.744.6-121.6148.4-161.4110.5102.1-91.1101.0149.256.816.2292.8-53.8-191.5165.1
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect ▁█▃▄▄▇▅▃▄▅-541.0666.5-167.2-33.1-77.8419.7102.4-238.332.3147.9NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:DeferredIncomeTaxExpenseBenefit ▇▇▇▇█▇▇▇▇▇▇▇▇█▁███▇███████████▇█▇▇▇▇█▇█▇▇▇▇▇▇▇8.22.5-0.76.516.37.04.710.210.05.7-8.86.82.518.7-305.314.413.916.5-10.835.322.525.834.415.816.024.018.615.016.811.08.534.06.84.3-7.410.011.110.712.08.26.44.3-1.75.22.45.1
us-gaap:NetCashProvidedByUsedInOperatingActivities NANA134.7102.8146.353.0165.5121.3111.564.3167.2134.6129.577.2179.393.3172.252.0193.1194.1161.477.5222.3120.5135.755.8163.9117.2116.751.4147.7124.1104.724.2145.6112.384.128.2119.071.479.636.891.564.686.3-0.3
us-gaap:NetIncomeLoss ▁▂▁▂▂▂▂▂▂▂▂▂▂▂█▂▂▂▂▃▂▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▁▂▂▂▁▁▁▁▁▁5.536.517.847.939.346.356.645.168.041.549.247.038.876.3342.149.053.457.530.995.761.269.358.239.545.462.258.551.353.142.153.353.835.127.129.753.823.530.331.632.926.419.919.521.121.518.7
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInInvestingActivities NANA-402.5-214.5-163.8-124.1-122.7-135.2-83.2-98.6-361.8-80.7-150.6-83.0-122.0-136.4-13.2-156.7-120.47.5-156.8-125.2-14.0-73.2-134.0-86.4-118.1-116.1-127.4-516.93.1-115.1-205.9-85.3-180.5-19.7-99.9-43.5-83.2-157.6-139.9-77.3-329.1-16.1-39.7-32.8
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment ▂█▃▃▂▂▃▂▂▁▆▂▂▂▁▁▂▁▂▁▂▁153.9509.5219.4249.9196.8194.7219.2191.1184.1147.3392.6169.7188.6178.4144.4127.1166.3129.0153.1120.4182.0140.2NANANANA188.6171.5209.6445.5192.8190.5219.4141.4241.2137.8209.1151.2138.7137.9120.069.8300.7104.047.767.8
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInFinancingActivities NANA99.775.8-313.5493.658.9-222.83.3182.542.5-35.928.7-56.738.6-42.2-31.6-48.724.3-167.9-41.860.5-121.210.7-295.6177.1106.6-50.1-326.1531.877.744.6-121.6148.4-161.4110.5102.1-91.1101.0149.256.816.2292.8-53.8-191.5165.1
us-gaap:ProceedsFromIssuanceOfLongTermDebt ▁█▂▂▄▇▂▁▁▄▄▁▃▁▄▁▁▃▁▃▂▃▁▁▁▅▃▂▁▆▃▁▂▅▂▁▃▁▃▂-1.50000000000011921074.1120.7117.8486.8861.2193.30.254.3495.2396.60.0297.10.0495.1-0.1-0.3297.957.6341.5137.6322.70.059.821.3667.7246.899.634.1842.5330.474.9129.0597.9132.330.7247.434.8244.4193.2NANA314.70.0NANA
us-gaap:RepaymentsOfLongTermDebt NANA0.00.0750.0350.00.0250.00.0160.0369.70.0251.411.7401.50.01.4300.11.3442.7153.7202.376.94.2264.1381.1136.917.1358.7307.1197.143.797.1264.9336.719.356.6258.635.754.6195.726.846.25.0241.151.9
us-gaap:PaymentsOfDividends ▆█▅▅▆▇▅▅▅▇▅▅▅▇▄▅▅▇▄▅▅▆▄▅▅▆▃▃▃▅▂▃▃▄▃▂▃▃▂▂▂▂▁▁▁▂18.219.717.317.317.419.016.516.617.019.216.617.017.118.616.416.616.818.416.216.516.618.116.316.717.218.014.914.915.316.914.514.715.016.315.214.114.814.713.713.913.914.513.213.213.213.9
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value4242414141414141414141414141414141414141414141414141414141414141414141414141414141404040
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.70.70.70.70.70.70.70.70.70.70.70.80.8

us-gaap:CommonStockValue us-gaap:StatementEquityComponents

us-gaap:CommonStock


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value4242414141414141414141414141414141414141414040
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.70.70.80.8
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Shares Issued

us-gaap:SharesIssued us-gaap:StatementEquityComponents

us-gaap:SharesIssued

us-gaap:TreasuryStock


Shares
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-32.7-32.7-32.7-32.7-32.7-32.7-32.7-32.4-31.8-31.2-30.7-29.7-29.6-29.6-29.2-27.5-24.8-22.4-20.5-19.1-19.1-19.1-19.1-16.3-14.2
Percentage of SharesIssued100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Common Stock Shares Issued

us-gaap:CommonStockSharesIssued us-gaap:StatementEquityComponents

us-gaap:CommonStockSharesIssued

us-gaap:CommonStock


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value6868676767676767676767676767676766666666656565
Percentage of CommonStockSharesIssued100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value3635353535363637383838393939404141434444454646464747474747474747464647
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value3535353434353636373737383939404041424344444546464646464646464646464646
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.161.040.511.371.121.331.621.281.891.141.321.251.032.028.981.271.371.460.782.391.511.671.380.921.041.411.321.161.170.921.161.160.750.580.631.150.50.650.680.710.570.430.420.450.470.41
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.151.020.51.351.111.311.591.251.861.121.31.221.011.988.831.251.351.440.772.361.491.661.370.911.031.391.31.141.150.91.141.150.740.570.621.130.490.640.670.70.560.420.420.450.460.4
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Income Loss From Continuing Operations Per Basic Share

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare

us-gaap:IncomeLossFromContinuingOperationsPerBasicShare


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value0.161.040.511.381.061.351.211.051.681.13
Percentage of IncomeLossFromContinuingOperationsPerBasicShare100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Income Loss From Continuing Operations Per Diluted Share

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare

us-gaap:IncomeLossFromContinuingOperationsPerDilutedShare


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value0.151.020.51.361.051.331.181.031.651.11
Percentage of IncomeLossFromContinuingOperationsPerDilutedShare100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Allocated Share Based Compensation Expense

us-gaap:AllocatedShareBasedCompensationExpense

us-gaap:AllocatedShareBasedCompensationExpense


Allocated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value3.96.06.13.93.72.25.64.14.55.13.95.74.74.93.73.43.93.26.73.22.93.02.72.83.22.94.73.13.13.13.63.13.23.23.13.03.03.14.12.02.42.5
Percentage of AllocatedShareBasedCompensationExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.22.02.01.31.20.71.61.11.31.61.11.61.31.61.00.91.11.01.90.90.80.90.70.70.90.91.20.80.81.11.00.90.91.20.90.90.91.11.20.60.80.9

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax


Comprehensive
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value233.04070588.2821182364249-7.59136166977710102379441405913-4.75.55344113104391327668.259-19.6-23.844502365-40.2
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues7.41.013.323.119.52.723.03.322.911.411.914.1-2.130.0102.618.528.024.53.028.210.428.210.910.616.24.3-1.21.414.715.631.729.711.65.08.419.32.421.0-5.9-7.014.219.07.821.3-13.9

Income Loss From Continuing Operations

us-gaap:IncomeLossFromContinuingOperations

us-gaap:IncomeLossFromContinuingOperations


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value5.5361748374742376041
Percentage of IncomeLossFromContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.711.95.815.812.315.311.810.316.813.0

Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value5037173723393644673529483482245763699.7121819273585780655861465250302633324038
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues16.012.35.812.28.012.910.112.318.811.18.213.810.027.17.015.918.122.02.733.522.727.719.515.115.725.216.214.816.716.214.614.29.19.610.09.511.713.4

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value138.47.7114.7121211158.4-8.7139.120-304.0201920-2.9412630422020272119201417319.17.5-0.2-2.2151311109.35.9-1.97.23.77.6
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues4.32.72.53.91.64.23.53.34.32.6-2.43.72.66.7-86.25.75.56.5-0.811.37.49.211.35.35.78.45.45.05.54.94.98.92.72.8-0.1-0.64.54.63.53.23.02.2-0.62.31.32.9

us-gaap:IncomeTaxExpenseBenefit us-gaap:StatementEquityComponents

gmt:ParentAndEquityMethodInvestments


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value58108.2359.51720141911-6.9151223-301.6242223-1.2412833391723302524251824271811
Percentage of IncomeTaxExpenseBenefit430.9121.4106.5303.4202.1133.3164.0125.2122.4141.779.3120.6134.1115.599.2119.1114.0114.641.499.8105.2108.891.486.2114.4111.1119.1123.1126.7129.8138.688.2202.2154.7
Percentage of Revenues18.53.32.711.83.25.65.74.15.33.8-1.94.53.57.8-85.56.86.37.5-0.311.37.810.010.34.56.59.46.46.27.06.46.87.85.44.3
Percentage of Revenues gmt:ParentAndEquityMethodInvestments0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value50534848474646464746434242394140403938363637383738403838394241414340394241424240434242414142
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues15.817.516.016.015.815.213.112.813.114.712.312.212.113.111.611.211.512.410.510.010.211.110.09.810.512.89.79.610.814.711.611.612.715.011.912.512.115.012.712.113.716.213.713.414.316.2

us-gaap:InterestExpense us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Interest
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value1.91.3-2.2-1.6-1.3-1.2-1.4-1.5-1.7-1.8-2.2-2.0-2.6-2.6-2.4-0.3-3.2-7.71.4-0.9-0.60.3-2.44.03.41.10.80.53.01.10.41.01.31.41.80.81.4
Percentage of InterestExpense3.82.4-4.5-3.4-2.8-2.6-3.0-3.2-3.7-4.1-5.2-4.7-6.5-6.3-6.0-0.8-8.2-20.23.9-2.5-1.60.8-6.410.48.32.82.11.37.12.71.02.33.23.54.21.93.3
Percentage of Revenues0.60.4-0.7-0.5-0.4-0.3-0.4-0.4-0.5-0.5-0.6-0.6-0.9-0.7-0.7-0.1-1.0-2.10.4-0.3-0.20.1-0.61.11.10.30.20.11.00.30.10.30.50.40.50.20.5
Percentage of Revenues gmt:OtherBusinessSegments22.627.70.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0900.0266.7700.0

gmt:PortfolioManagement


Interest
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value4.43.13.23.02.92.92.82.82.72.82.62.72.32.42.22.42.215-2.12.12.24.54.75.65.25.65.86.16.87.06.36.76.77.16.96.57.2
Percentage of InterestExpense8.85.86.66.36.26.26.05.95.86.46.16.45.85.85.56.05.639.3-5.85.85.911.812.514.512.714.415.215.416.216.915.315.516.418.016.115.616.9
Percentage of Revenues1.41.01.11.00.90.80.80.80.90.80.70.80.80.70.60.70.74.1-0.60.60.71.21.21.51.61.41.51.72.42.01.82.02.52.12.01.92.5
Percentage of Revenues gmt:PortfolioManagement32.443.761.578.980.60.0121.7466.796.40.076.565.947.90.046.827.017.90.0-18.116.512.00.021.026.021.20.023.329.028.70.025.133.841.60.038.834.025.6

gmt:RailInternational


Interest
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value11121111101010109.99.48.98.98.78.98.58.17.951-7.37.37.35.97.03.06.56.36.06.26.26.46.75.25.65.56.16.56.4
Percentage of InterestExpense22.222.824.524.322.622.322.021.421.321.420.921.121.821.721.120.220.2135.1-20.220.019.615.518.67.815.916.215.715.714.815.516.312.013.713.914.215.615.0
Percentage of Revenues3.54.03.93.83.42.92.82.83.12.62.52.52.82.52.42.32.514.3-2.02.02.21.61.80.82.01.61.51.72.21.81.91.52.11.71.81.92.2
Percentage of Revenues gmt:RailInternational15.517.617.718.817.60.017.618.118.30.016.516.416.00.016.316.917.80.0-15.115.615.70.015.36.814.80.012.012.412.60.014.111.512.40.014.716.015.6

gmt:RailNorthAmerica


Interest
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value3237353433333334343231313031302831191-27.1262726272424242425242526282523262525
Percentage of InterestExpense65.269.073.572.871.270.971.572.473.573.174.673.775.775.775.971.279.3500.8-74.973.773.168.471.663.959.962.963.364.158.661.663.566.462.860.561.362.360.6
Percentage of Revenues10.312.111.711.510.89.39.29.510.89.09.18.99.98.88.58.29.852.8-7.57.58.16.97.06.77.76.16.16.98.67.27.48.59.47.27.77.69.1
Percentage of Revenues gmt:RailNorthAmerica14.616.515.414.614.10.013.914.113.80.013.613.112.80.012.611.712.30.0-10.810.710.30.010.69.910.10.010.110.811.70.012.614.313.00.013.613.713.8

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value5.53617473946564568414947387634249535730956169583945625851534253533527295323303132261919212118
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.711.95.815.713.115.015.912.518.913.113.813.411.125.097.013.615.318.28.526.417.120.715.410.212.419.514.612.914.514.714.915.210.410.09.015.76.910.79.69.78.47.56.46.87.57.1

Operating Costs And Expenses

us-gaap:OperatingCostsAndExpenses

us-gaap:OperatingCostsAndExpenses


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value1951881851841881992332292321942232182221922252262231882332242331852342382321932642572431802402392351784981361307813712712290
Percentage of OperatingCostsAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues61.661.760.760.562.864.565.563.564.661.562.762.663.763.163.963.064.159.564.561.764.955.561.961.663.560.665.864.966.662.967.567.769.565.7150.439.638.027.741.737.639.034.0

us-gaap:OperatingCostsAndExpenses us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Operating
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value4.72.80.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.10.0-0.10.0-0.10.0-0.10.0-0.10.0-0.10.0-0.10.0-0.1-0.10.1-0.10.90.30.40.1
Percentage of OperatingCostsAndExpenses2.41.50.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.0-0.10.1-0.10.70.20.30.1
Percentage of Revenues1.50.90.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.00.0-0.0-0.00.0-0.00.30.10.10.0
Percentage of Revenues gmt:OtherBusinessSegments56.059.60.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-50.033.3-50.00.0100.080.050.0

gmt:PortfolioManagement


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value107.5105.04.75.58.95.15.86.35.36.36.26.37.76.09.59.69.29.71311181619181819181717171512335.15.90.9113.93.33.4
Percentage of OperatingCostsAndExpenses5.64.05.62.72.52.83.82.22.53.22.42.92.83.33.42.64.35.13.94.35.96.28.07.18.29.56.97.47.69.77.47.36.77.16.63.84.51.18.13.12.73.8
Percentage of Revenues3.42.53.41.61.61.82.51.41.62.01.51.81.82.12.21.72.73.02.52.73.83.55.04.45.25.84.54.85.16.15.05.04.74.79.91.51.70.33.41.21.01.3
Percentage of Revenues gmt:PortfolioManagement80.1105.60.096.2123.7152.80.0221.7966.7225.00.0185.3151.2131.20.0127.7106.778.00.083.6107.963.00.075.488.875.10.076.788.673.80.069.780.378.90.028.730.93.20.016.518.821.4

gmt:RailInternational


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value3435333229302828262726252628242522222323252524222120252424242423212223192222
Percentage of OperatingCostsAndExpenses17.618.918.017.515.515.212.312.311.514.211.611.511.914.610.911.010.211.910.210.511.013.510.39.29.410.69.59.410.013.610.19.69.212.64.614.617.428.2
Percentage of Revenues10.811.710.910.69.79.88.07.87.48.77.37.27.69.27.07.06.57.16.66.57.17.56.45.76.06.46.26.16.78.66.86.56.48.37.05.86.67.8
Percentage of Revenues gmt:RailInternational47.851.40.048.047.750.20.048.447.950.90.046.648.751.70.047.847.550.50.048.854.653.80.048.049.446.60.048.048.750.00.048.447.749.80.047.755.954.3

gmt:RailNorthAmerica


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value145142141147154156150147151153142142146149145149149149155147151146147148143147154147145134139138137133132130125125
Percentage of OperatingCostsAndExpenses74.475.676.479.882.078.564.464.565.378.663.864.965.777.664.665.766.979.666.465.665.278.663.162.461.976.358.457.159.574.757.857.858.374.526.695.796.5159.5
Percentage of Revenues45.846.646.448.351.550.642.241.042.248.340.040.641.849.041.341.442.947.442.940.542.343.739.038.539.346.238.437.039.747.039.039.140.548.940.037.936.744.1
Percentage of Revenues gmt:RailNorthAmerica65.063.50.063.465.866.40.062.062.861.70.060.861.563.50.061.561.459.40.058.760.355.20.058.258.060.70.061.761.964.20.066.968.367.40.067.366.767.3

Operating Expenses

us-gaap:OperatingExpenses

us-gaap:OperatingExpenses


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value243235231226232241286273277241276265268237278269266231280272273224292282276239320303288223289281281220543174169116180165160126
Percentage of OperatingExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues76.677.175.974.377.378.280.475.877.176.077.775.976.977.878.874.976.473.177.575.076.367.177.173.175.774.979.776.478.977.881.179.683.181.1163.850.849.441.154.749.050.947.7

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-8100000.0-1300000.0-800000.0-1200000.0-3000000.0-8200000.0-2300000.0-1800000.0-600000.0-3200000.0-6700000.0-3800000.0-9800000.0-1300000.0-6600000.0-2100000.0-1100000.0-1300000.0-8900000.04300000.0-3900000.0-3300000.0-4500000.0-3100000.0-1600000.0-4000000.0-2100000.0-3100000.0-4900000.0-3400000.0200000.0-4400000.0-3100000.0-1100000.0-4200000.0-3900000.0500000.0-600000.0
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues-2.6-0.4-0.3-0.4-1.0-2.7-0.6-0.5-0.2-1.0-1.9-1.1-2.8-0.4-1.9-0.6-0.3-0.4-2.51.2-1.1-1.0-1.2-0.8-0.4-1.3-0.5-0.8-1.3-1.20.1-1.2-0.9-0.4-1.3-1.10.1-0.2

us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-7300000.0-500000.0200000.0-600000.0-1000000.0-1700000.0-2000000.0-600000.0-400000.0-200000.0-5400000.0-2700000.0-1200000.0-200000.0-4400000.0-1500000.0400000.0-100000.0-2800000.0300000.0-1300000.0200000.0100000.0-100000.0500000.0-1800000.00200000.0-1700000.0-300000.0400000.0500000.0200000.0-200000.0300000.0300000.0200000.0200000.0
Percentage of OtherNonoperatingIncomeExpense90.138.5-25.050.033.320.787.033.366.76.280.671.112.215.466.771.4-36.47.731.57.033.3-6.1-2.23.2-31.245.0-0.0-6.534.78.8200.0-11.4-6.518.2-7.1-7.740.0-33.3
Percentage of Revenues-2.3-0.20.1-0.2-0.3-0.6-0.6-0.2-0.1-0.1-1.5-0.8-0.3-0.1-1.2-0.40.1-0.0-0.80.1-0.40.10.0-0.00.1-0.60.00.1-0.5-0.10.10.10.1-0.10.10.10.10.1
Percentage of Revenues gmt:OtherBusinessSegments-86.9-10.60.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0150.066.7100.0

gmt:RailInternational


Other
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value200000.0700000.0500000.0-700000.0-5500000.01700000.0-100000.01900000.0-2300000.0300000.0200000.0-7300000.0-200000.0-900000.0300000.0-1100000.0-1500000.0-1200000.05500000.0-1300000.0-2200000.0-3000000.0-1800000.0-1200000.00700000.0-1100000.0-2700000.00-600000.0-1000000.00500000.0-2800000.0-1800000.0300000.0-1800000.0
Percentage of OtherNonoperatingIncomeExpense-2.5-87.5-41.723.367.1-73.95.6-316.771.9-4.5-5.374.515.413.6-14.3100.0115.413.5127.933.366.766.758.175.0-0.0-33.335.555.1-0.0-300.022.7-0.0-45.566.746.260.0300.0
Percentage of Revenues0.10.20.2-0.2-1.80.5-0.00.5-0.70.10.1-2.1-0.1-0.30.1-0.3-0.5-0.31.5-0.4-0.7-0.8-0.5-0.30.00.2-0.3-0.70.0-0.2-0.30.00.2-0.8-0.50.1-0.6
Percentage of Revenues gmt:RailInternational0.30.00.7-1.1-9.20.0-0.23.4-4.20.00.4-13.4-0.40.00.6-2.3-3.40.011.4-2.8-4.70.0-3.9-2.70.00.0-2.2-5.40.00.0-2.10.01.10.0-4.30.7-4.4

gmt:RailNorthAmerica


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-1000000.0-800000.0-1700000.0-1100000.0-1300000.0-800000.0-1700000.0-1000000.0-1900000.0-700000.0-1900000.0-1200000.0-1200000.0-900000.0-1800000.0-900000.0-1200000.0-2000000.0200000.0-1400000.0-1100000.0-1300000.0-1000000.0-1200000.0-800000.0-2200000.0-2500000.0-1000000.0-300000.0-3400000.0-900000.0-4800000.0-3300000.0-800000.0-1200000.0-1800000.0-200000.0-1900000.0
Percentage of OtherNonoperatingIncomeExpense12.361.5212.591.743.39.873.955.6316.721.928.431.612.269.227.342.9109.1153.8-2.2-32.628.239.422.238.750.055.0119.032.36.1100.0-450.0109.1106.572.728.646.2-40.0316.7
Percentage of Revenues-0.3-0.3-0.6-0.4-0.4-0.3-0.5-0.3-0.5-0.2-0.5-0.3-0.3-0.3-0.5-0.3-0.3-0.60.1-0.4-0.3-0.4-0.3-0.3-0.2-0.7-0.6-0.3-0.1-1.2-0.3-1.4-1.0-0.3-0.4-0.5-0.1-0.7
Percentage of Revenues gmt:RailNorthAmerica-0.4-0.40.0-0.5-0.6-0.30.0-0.4-0.8-0.30.0-0.5-0.5-0.40.0-0.4-0.5-0.80.0-0.6-0.4-0.50.0-0.5-0.3-0.90.0-0.4-0.1-1.60.0-2.3-1.6-0.40.0-0.9-0.1-1.0

Revenues

us-gaap:Revenues

us-gaap:Revenues


Revenues
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value317305304304300308356360359317356349349305352359348316362362358334378386365319401397365286356353338272331343343284330337314265306308288263
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Revenuesus-gaap:
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value8.44.70.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.70.20.30.20.10.30.50.22.00.20.7
Percentage of Revenues2.61.50.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.20.10.10.10.00.10.20.10.70.10.2
Percentage of Revenues2.61.50.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.20.10.10.10.00.10.20.10.70.10.2
Percentage of Revenues gmt:OtherBusinessSegments100.0100.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:PortfolioManagement


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value137.14.45.23.83.64.22.30.62.83.83.44.14.84.04.78.912131112182422212427242123262519161.817192826231715
Percentage of Revenues4.32.31.41.71.31.21.20.60.20.91.11.01.21.61.11.32.63.93.83.23.55.56.45.85.97.76.96.35.78.37.37.15.85.90.55.25.69.97.97.05.66.0
Percentage of Revenues4.32.31.41.71.31.21.20.60.20.91.11.01.21.61.11.32.63.93.83.23.55.56.45.85.97.76.96.35.78.37.37.15.85.90.55.25.69.97.97.05.66.0
Percentage of Revenues gmt:PortfolioManagement100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:RailInternational


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value7169696761605958555454545454525247444748464646454444495050495147454544414040
Percentage of Revenues22.622.722.922.020.419.516.816.115.517.115.315.515.617.814.914.513.714.013.113.313.113.912.311.912.113.812.312.613.717.214.313.413.416.613.512.111.814.4
Percentage of Revenues22.622.722.922.020.419.516.816.115.517.115.315.515.617.814.914.513.714.013.113.313.113.912.311.912.113.812.312.613.717.214.313.413.416.613.512.111.814.4
Percentage of Revenues gmt:RailInternational100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:RailNorthAmerica


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value223224230232235235236238241248235233237235240242243252252250251264260255247243245238234209211206201197196193188186
Percentage of Revenues70.573.475.776.278.476.366.366.167.178.366.066.768.077.168.067.469.779.769.669.070.279.168.866.167.876.161.160.064.173.159.458.559.372.659.356.355.065.5
Percentage of Revenues70.573.475.776.278.476.366.366.167.178.366.066.768.077.168.067.469.779.769.669.070.279.168.866.167.876.161.160.064.173.159.458.559.372.659.356.355.065.5
Percentage of Revenues gmt:RailNorthAmerica100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Selling General And Administrative Expense

us-gaap:SellingGeneralAndAdministrativeExpense

us-gaap:SellingGeneralAndAdministrativeExpense


Selling
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value47474642434253444546534646445242434246484038574444455545444248424542443838384338373637313233
Percentage of SellingGeneralAndAdministrativeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues15.115.415.213.814.413.714.912.312.514.515.013.313.214.714.911.912.413.613.013.311.411.615.211.512.214.313.911.512.314.913.611.913.515.413.411.211.313.413.011.411.913.712.210.011.412.7

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value94009915893786908512871782858090835382407616751774957468742272617272709671057089709070626894690468607056693768166921711965496339611961446055612559175792585757565642549854425206
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assetsus-gaap:
Period End2020-12-312019-12-31
Value51195219
Percentage of Assets57.363.0
Percentage of Assets57.363.0
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees100.0100.0

us-gaap:Assets us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assetsus-gaap:
Period End2020-12-312019-12-31
Value51195218
Percentage of Assets57.363.0
Percentage of Assets57.363.0
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees100.0100.0

Liabilities

us-gaap:Liabilities

us-gaap:Liabilities


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value74297955698067606637688664506304651864315828567956775628562957915829571157585717578257565614563555745773562354855546569551525027490049214811489947474617473046014451434543284103
Percentage of Liabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets79.080.278.177.878.079.077.977.978.078.076.575.675.875.475.879.880.280.581.080.781.581.581.481.681.381.881.180.580.180.078.779.380.180.179.580.080.279.780.879.978.979.079.578.8

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value94009915893786908512871782858090835382407616751774957468742272617272709671057089709070626894690468607056693768166921711965496339611961446055612559175792585757565642549854425206
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value51195219
Percentage of LiabilitiesAndStockholdersEquity57.363.0
Percentage of Assets57.363.0
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value51195218
Percentage of LiabilitiesAndStockholdersEquity57.363.0
Percentage of Assets57.363.0
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-31
Value197119601957193018751831183517861834180917881838181718391792147014431385134713711308130512801269128512821314133113741423139713121219122312441225117011751127115511911153111311021124
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets21.019.821.922.222.021.022.122.122.022.023.524.424.224.624.220.219.819.519.019.318.518.518.618.418.718.218.919.519.920.021.320.719.919.920.520.019.820.319.220.121.121.020.521.20.0

us-gaap:StockholdersEquity us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value-137.5-163.6-164.6-109.6
Percentage of StockholdersEquity-7.0-8.9-9.2-6.1
Percentage of Assets-1.5-2.0-2.2-1.5
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.0

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:RetainedEarnings


Stockholders
Period End2020-12-312019-12-312018-12-31
Value268226012419
Percentage of StockholdersEquity137.0141.8135.3
Percentage of Assets30.031.431.8
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:RetainedEarnings0.00.00.0

us-gaap:StockholdersEquity us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Stockholders
Period End2020-12-312019-12-31
Value1133990
Percentage of StockholdersEquity57.954.0
Percentage of Assets12.712.0
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees22.119.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-153.0-171.0-137.5-160.2-182.5-201.7-163.6-189.0-155.8-170.1-164.6-157.8-160.0-113.7-109.6-211.1-198.8-148.4-42.7-144.6169-110.0-84.5-85.286
Percentage of StockholdersEquity-7.8-8.7-7.0-8.3-9.7-11.0-8.9-10.6-8.5-9.4-9.2-8.6-8.8-6.2-6.1-15.7-15.5-11.3-3.1-11.615.0-9.9-7.7-7.60.0
Percentage of Assets-1.6-1.7-1.5-1.8-2.1-2.3-2.0-2.3-1.9-2.1-2.2-2.1-2.1-1.5-1.5-3.0-2.9-2.1-0.7-2.42.9-2.0-1.60.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value759753735730728725720716713709706703702699698687677672668658644626616611531
Percentage of StockholdersEquity38.538.437.637.938.939.639.240.138.939.239.538.338.738.038.951.152.951.247.952.957.256.255.954.40.0
Percentage of Assets8.17.68.28.48.68.38.78.98.58.69.39.49.49.49.49.79.89.710.210.911.011.511.80.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value268727002682268226512630260125612533248224192387235723352261182816391501135812491171111610901062920
Percentage of StockholdersEquity136.3137.8137.0139.0141.4143.6141.8143.4138.1137.2135.3129.9129.7127.0126.2135.7128.0114.397.2100.4103.9100.398.994.50.0
Percentage of Assets28.627.230.030.931.130.231.431.730.330.131.831.831.431.330.525.723.821.620.720.620.020.520.90.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-1364.5-1364.5-1364.5-1364.5-1364.5-1364.5-1364.5-1344.4-1297.7-1254.5-1214.5-1136.4-1124.0-1124.0-1099.0-999.0-878.9-753.5-628.9-560.3-560.3-560.3-560.3-505.2-428.7
Percentage of StockholdersEquity-69.2-69.6-69.7-70.7-72.8-74.5-74.4-75.3-70.7-69.3-67.9-61.8-61.8-61.1-61.3-74.2-68.7-57.3-45.0-45.0-49.7-50.3-50.8-44.90.0
Percentage of Assets-14.5-13.8-15.3-15.7-16.0-15.7-16.5-16.6-15.5-15.2-15.9-15.1-15.0-15.1-14.8-14.1-12.7-10.9-9.6-9.3-9.6-10.3-10.80.00.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:AssetsCurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value352203
Percentage of AssetsCurrent100.0100.0
Percentage of Assets3.92.5
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees6.93.9

us-gaap:AssetsCurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value352202
Percentage of AssetsCurrent100.099.5
Percentage of Assets3.92.4
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees6.93.9

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:CashAndCashEquivalentsAtCarryingValue


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value41795829245949257015148286248100254237233296199284155307211177216202116583512095911044737915096321234430227141248115505378232917341102104
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets4.49.73.35.35.86.51.80.63.43.01.33.43.23.14.02.73.92.24.33.02.53.12.91.70.95.03.00.91.66.35.82.41.65.23.97.03.82.44.22.00.91.01.40.00.00.00.80.00.0

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302015-12-312014-12-31
Value41895929245949257015148286254106258241237299202288159311215219224
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets4.49.73.35.35.86.51.80.63.43.11.43.43.23.24.02.84.02.24.43.03.23.2

Assets Noncurrent

us-gaap:AssetsNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:AssetsNoncurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value47665015
Percentage of AssetsNoncurrent100.0100.0
Percentage of Assets53.360.5
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees93.196.1

Property Plant And Equipment Gross

us-gaap:PropertyPlantAndEquipmentGross

us-gaap:PropertyPlantAndEquipmentGross


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-31
Value1092310835104841007097849972989797599728958795659262920691919045891588018631844685458508844082048141834181948143811080917958739074007198691868556416
Percentage of PropertyPlantAndEquipmentGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets116.2109.3117.3115.9114.9114.4119.5120.6116.5116.4125.6123.2122.8123.1121.9122.8121.0121.6118.9120.5120.0119.5119.0117.9121.6116.1117.4119.0116.9111.8112.8116.7117.6112.6113.2109.5

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value33403311331332263155322231903152312230623015296529112897285328142743266626412633258025632505248725062434245524252402235823202291223922242200214921072107205620612080208620492041
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets35.533.437.137.137.137.038.539.037.437.239.639.438.838.838.438.837.737.637.237.136.436.336.336.036.534.535.435.634.733.135.436.236.636.236.335.135.636.435.135.836.937.937.739.2

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value1283117810249431007993
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment38.736.934.033.138.139.7
Percentage of Assets14.414.213.512.714.214.4
Percentage of Assets gmt:RrpfJointVentures0.00.00.00.00.00.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value75827523717068446628675067076607660665256549629762946294619261016058596558045912592858765698565358345759568856845688559950705108495846934654450845084460435943384261418941334033
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets80.775.980.278.877.977.481.081.779.179.286.083.884.084.383.484.083.384.181.783.483.683.282.781.985.081.682.083.482.278.777.480.681.076.476.973.676.277.074.475.475.576.276.077.5

us-gaap:PropertyPlantAndEquipmentNet us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, us-gaap:FairValueByMeasurementFrequency, us-gaap:InvestmentType

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


Property
Period End2020-12-312019-12-312018-12-31
Value1.71.610
Percentage of PropertyPlantAndEquipmentNet0.00.00.2
Percentage of Assets0.00.00.1
Percentage of Assets us-gaap:FairValueInputsLevel3 us-gaap:EstimateOfFairValueFairValueDisclosure us-gaap:FairValueMeasurementsNonrecurring us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.0

Investments In Affiliates Subsidiaries Associates And Joint Ventures

us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures

us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures


Investments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value561592584582551532512506495480464478468455441449407396387376361356348364368359357348356348354361424485502532519509513547567524486452
Percentage of InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets6.06.06.56.76.56.16.26.35.95.86.16.46.36.15.96.25.65.65.45.35.15.05.15.35.45.15.25.15.24.95.45.76.97.98.38.78.88.88.89.510.19.58.98.7

us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:StatementBusinessSegments

gmt:RollsRoycePartnersFinance, gmt:PortfolioManagement


Investments
Period End2020-12-312019-12-31
Value584512
Percentage of InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures100.0100.0
Percentage of Assets6.56.2
Percentage of Assets gmt:RollsRoycePartnersFinance gmt:PortfolioManagement0.00.0

us-gaap:InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures us-gaap:StatementBusinessSegments

gmt:PortfolioManagement


Investments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-312009-12-31
Value561592584582551532512506495479464474462449434439396385375365348344335350353344338327336324320328307358377406391371371345331
Percentage of InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures99.9100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.298.598.598.597.897.197.197.096.996.696.596.296.295.995.794.794.294.393.290.690.772.473.975.376.375.373.072.371.073.3
Percentage of Assets6.06.06.56.76.56.16.26.35.95.86.16.36.26.05.86.15.45.45.35.14.94.94.95.15.24.94.94.84.94.64.95.25.05.86.26.66.66.46.36.36.4
Percentage of Assets gmt:PortfolioManagement0.00.00.00.00.081.078.479.278.877.676.577.276.375.174.571.366.564.263.260.256.556.852.647.544.443.341.640.239.138.037.438.637.146.847.449.848.644.744.046.649.2

gmt:RailNorthAmerica


Investments
Period End2021-06-302020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value0.40.20.20.20.20.20.20.20.23.76.86.86.89.8101010101010121213131718182131313347464646465459
Percentage of InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures0.10.00.00.00.00.00.00.00.00.81.51.51.52.22.62.62.72.83.03.13.43.43.63.94.85.35.26.38.98.77.99.79.38.89.09.210.512.2
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.10.10.10.10.10.10.10.10.20.20.20.20.20.20.20.30.30.30.50.50.50.80.80.80.80.80.91.1
Percentage of Assets gmt:RailNorthAmerica0.00.00.00.00.00.00.00.00.00.10.10.10.10.20.20.20.20.20.20.20.30.30.30.30.40.40.40.50.80.80.91.31.31.31.31.31.51.8

Goodwill

us-gaap:Goodwill

us-gaap:Goodwill


Goodwill
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1401391438481808179828182838487858482787881818279818179868894949493908991908992909298969297
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.51.41.61.01.00.91.01.01.01.01.11.11.11.21.21.21.11.11.11.21.11.21.21.21.21.11.21.31.41.31.41.51.51.51.51.51.51.61.51.61.71.81.71.9

us-gaap:Goodwill us-gaap:BusinessAcquisition

gmt:TrifleetLeasingHoldingBV


Goodwillus-gaap:
Period End2020-12-29
Value57
Percentage of Goodwill0.0
Percentage of Assets0.0
Percentage of Assets gmt:TrifleetLeasingHoldingBV0.0

us-gaap:Goodwill us-gaap:StatementBusinessSegments

gmt:RailInternational


Goodwillus-gaap:
Period End2020-12-312019-12-31
Value6257
Percentage of Goodwill43.870.8
Percentage of Assets0.70.7
Percentage of Assets gmt:RailInternational0.03.9

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OperatingLeaseRightOfUseAsset


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value2863263353643724024134304404490.0
Percentage of OperatingLeaseRightOfUseAsset100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0
Percentage of Assets3.03.33.84.24.44.65.05.35.35.50.0

Other Assets

us-gaap:OtherAssets

us-gaap:OtherAssets


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value218226230227225243238237237239206191197194190208223291297265270278312409243244229257264243225192197192186184191195180197200193187183
Percentage of OtherAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.32.32.62.62.72.82.92.92.82.92.72.52.62.62.62.93.14.14.23.83.83.94.55.93.53.53.33.83.83.43.43.03.23.13.13.03.23.43.13.43.53.53.43.5

Liabilities Current

us-gaap:LiabilitiesCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:LiabilitiesCurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value311525
Percentage of LiabilitiesCurrent100.0100.0
Percentage of Assets3.56.3
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees6.110.1

us-gaap:LiabilitiesCurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value200429
Percentage of LiabilitiesCurrent64.581.7
Percentage of Assets2.25.2
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees3.98.2

Liabilities Noncurrent

us-gaap:LiabilitiesNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:LiabilitiesNoncurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value36743703
Percentage of LiabilitiesNoncurrent100.0100.0
Percentage of Assets41.144.7
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees71.871.0

us-gaap:LiabilitiesNoncurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value32433367
Percentage of LiabilitiesNoncurrent88.390.9
Percentage of Assets36.340.6
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees63.464.5

Long Term Debt

us-gaap:LongTermDebt

us-gaap:LongTermDebt


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value53584813447344124286420542033838328335043019
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets60.058.158.759.460.361.060.658.654.259.855.5

us-gaap:LongTermDebt us-gaap:LineOfCreditFacility

us-gaap:ForeignLineOfCredit


Long
Period End2020-12-31
Value580
Percentage of LongTermDebt10.8
Percentage of Assets6.5
Percentage of Assets us-gaap:ForeignLineOfCredit0.0

us-gaap:LongTermDebt us-gaap:LongtermDebtType

gmt:RecourseFloatingRateDebtUnsecuredOne


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value3003003002000.0
Percentage of LongTermDebt5.66.26.74.50.0
Percentage of Assets3.43.63.92.70.0
Percentage of Assets gmt:RecourseFloatingRateDebtUnsecuredOne0.00.00.00.00.0

us-gaap:LongTermDebt us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value345438113469275324492387228920231996
Percentage of LongTermDebt64.579.277.662.457.256.854.552.760.8
Percentage of Assets38.746.045.537.134.534.633.030.933.0
Percentage of Assets gmt:RrpfJointVentures0.00.00.00.00.00.00.00.00.0

Deferred Income Tax Liabilities Net

us-gaap:DeferredIncomeTaxLiabilitiesNet

us-gaap:DeferredIncomeTaxLiabilitiesNet


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value971960962936915930924
Percentage of DeferredIncomeTaxLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets10.39.710.810.810.810.711.2

Minority Interest

us-gaap:MinorityInterest us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:MinorityInterest

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Minority
Period End2020-12-312019-12-31
Value1133989
Percentage of MinorityInterest100.0100.0
Percentage of Assets12.711.9
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees22.119.0

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent


Other
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value43334329423336313233
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.50.40.60.40.60.50.50.50.50.6

Operating Lease Liability

us-gaap:OperatingLeaseLiability

us-gaap:OperatingLeaseLiability


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value2983283483683723994324404544560.0
Percentage of OperatingLeaseLiability100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0
Percentage of Assets3.23.33.94.24.44.65.25.45.45.50.0

us-gaap:OperatingLeaseLiability gmt:OperatingLeasesByType

gmt:RecourseOperatingLeases


Operating
Period End2020-12-312019-12-31
Value348432
Percentage of OperatingLeaseLiability100.0100.0
Percentage of Assets3.95.2
Percentage of Assets gmt:RecourseOperatingLeases0.00.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-31
Value197119601957193018751831183517861834180917881838181718391792147014431385134713711308130512801269128512821314133113741423139713121219122312441225117011751127115511911153111311021124
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets21.019.821.922.222.021.022.122.122.022.023.524.424.224.624.220.219.819.519.019.318.518.518.618.418.718.218.919.519.920.021.320.719.919.920.520.019.820.319.220.121.121.020.521.20.0

us-gaap:StockholdersEquity us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value-137.5-163.6-164.6-109.6
Percentage of StockholdersEquity-7.0-8.9-9.2-6.1
Percentage of Assets-1.5-2.0-2.2-1.5
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.0

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:RetainedEarnings


Stockholders
Period End2020-12-312019-12-312018-12-31
Value268226012419
Percentage of StockholdersEquity137.0141.8135.3
Percentage of Assets30.031.431.8
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:RetainedEarnings0.00.00.0

us-gaap:StockholdersEquity us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Stockholders
Period End2020-12-312019-12-31
Value1133990
Percentage of StockholdersEquity57.954.0
Percentage of Assets12.712.0
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees22.119.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-153.0-171.0-137.5-160.2-182.5-201.7-163.6-189.0-155.8-170.1-164.6-157.8-160.0-113.7-109.6-211.1-198.8-148.4-42.7-144.6169-110.0-84.5-85.286
Percentage of StockholdersEquity-7.8-8.7-7.0-8.3-9.7-11.0-8.9-10.6-8.5-9.4-9.2-8.6-8.8-6.2-6.1-15.7-15.5-11.3-3.1-11.615.0-9.9-7.7-7.60.0
Percentage of Assets-1.6-1.7-1.5-1.8-2.1-2.3-2.0-2.3-1.9-2.1-2.2-2.1-2.1-1.5-1.5-3.0-2.9-2.1-0.7-2.42.9-2.0-1.60.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value759753735730728725720716713709706703702699698687677672668658644626616611531
Percentage of StockholdersEquity38.538.437.637.938.939.639.240.138.939.239.538.338.738.038.951.152.951.247.952.957.256.255.954.40.0
Percentage of Assets8.17.68.28.48.68.38.78.98.58.69.39.49.49.49.49.79.89.710.210.911.011.511.80.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value268727002682268226512630260125612533248224192387235723352261182816391501135812491171111610901062920
Percentage of StockholdersEquity136.3137.8137.0139.0141.4143.6141.8143.4138.1137.2135.3129.9129.7127.0126.2135.7128.0114.397.2100.4103.9100.398.994.50.0
Percentage of Assets28.627.230.030.931.130.231.431.730.330.131.831.831.431.330.525.723.821.620.720.620.020.520.90.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-1364.5-1364.5-1364.5-1364.5-1364.5-1364.5-1364.5-1344.4-1297.7-1254.5-1214.5-1136.4-1124.0-1124.0-1099.0-999.0-878.9-753.5-628.9-560.3-560.3-560.3-560.3-505.2-428.7
Percentage of StockholdersEquity-69.2-69.6-69.7-70.7-72.8-74.5-74.4-75.3-70.7-69.3-67.9-61.8-61.8-61.1-61.3-74.2-68.7-57.3-45.0-45.0-49.7-50.3-50.8-44.90.0
Percentage of Assets-14.5-13.8-15.3-15.7-16.0-15.7-16.5-16.6-15.5-15.2-15.9-15.1-15.0-15.1-14.8-14.1-12.7-10.9-9.6-9.3-9.6-10.3-10.80.00.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value4242414141414141414141414141414141414141414141414141414141414141414141414141414141404040
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.60.70.70.70.70.70.70.70.70.70.70.70.80.8

us-gaap:CommonStockValue us-gaap:StatementEquityComponents

us-gaap:CommonStock


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value4242414141414141414141414141414141414141414040
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.70.70.80.8
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Additional Paid In Capital

us-gaap:AdditionalPaidInCapital

us-gaap:AdditionalPaidInCapital


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value759753735730728725720716713709706703702699698695693690687681679676677676673671672670667666668663660657658652649647644638636630626616
Percentage of AdditionalPaidInCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets8.17.68.28.48.68.38.78.98.58.69.39.49.49.49.49.69.59.79.79.69.69.69.89.89.89.59.79.89.69.410.210.510.810.710.910.711.011.211.011.111.311.511.511.8

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value26872700268226822651263026012561253324822419238723572335226119361904186818281813173416891639159715741547150114581422138413581320128112611249123411951186117111531134112211161090
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets28.627.230.030.931.130.231.431.730.330.131.831.831.431.330.526.726.226.325.725.624.523.923.823.123.021.921.621.420.619.420.720.820.920.520.620.220.220.520.020.020.120.420.520.9

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-31
Value-153.0-171.0-137.5-160.2-182.5-201.7-163.6-189.0-155.8-170.1-164.6-157.8-160.0-113.7-109.6-129.4-146.9-191.1-211.1-191.1-197.9-173.9-198.8-181.9-183.3-196.9-148.4-85.2-39.4-40.1-42.7-102.6-153.7-158.0-144.6-142.6-155.0-139.7-169.1-117.9-61.2-79.6-110.0-84.5-85.2
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-1.6-1.7-1.5-1.8-2.1-2.3-2.0-2.3-1.9-2.1-2.2-2.1-2.1-1.5-1.5-1.8-2.0-2.7-3.0-2.7-2.8-2.5-2.9-2.6-2.7-2.8-2.1-1.2-0.6-0.6-0.7-1.6-2.5-2.6-2.4-2.3-2.6-2.4-2.9-2.0-1.1-1.4-2.0-1.60.0

Treasury Stock Value

us-gaap:TreasuryStockValue

us-gaap:TreasuryStockValue


Treasury
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value136413641364136413641364136413441297125412141136112411241099107410491024999974949929878864821780753753717628628610610578560560560560560560560560560560
Percentage of TreasuryStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets14.513.815.315.716.015.716.516.615.515.215.915.115.015.114.814.814.414.414.113.713.413.212.712.512.011.110.911.110.48.89.69.610.09.49.39.19.59.79.69.79.910.210.310.8

Minority Interest

us-gaap:MinorityInterest us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:MinorityInterest

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Minority
Period End2020-12-312019-12-31
Value1133989
Percentage of MinorityInterest100.0100.0
Percentage of Assets12.711.9
Percentage of Assets gmt:RrpfJointVentures us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees22.119.0

Stock Issued During Period Value New Issues

us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents

us-gaap:StockIssuedDuringPeriodValueNewIssues

us-gaap:CommonStock


Stock
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312015-03-31
Value100000.0200000.00100000.00000100000.0100000.00000100000.0
Percentage of StockIssuedDuringPeriodValueNewIssues100.0100.00.0100.00.00.00.00.0100.0100.00.00.00.00.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

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

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AdditionalPaidInCapital


Adjustments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312015-03-31
Value6.3174.62.03.45.33.53.63.53.12.80.92.81.94.6
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1341021465316512111164167134129771799317252193194161772221201355516311711651147124104241451128428119717936916486-0.3
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 Revenues44.233.848.717.246.433.631.020.346.938.537.125.350.825.949.416.553.353.545.023.258.731.237.117.540.829.531.917.941.435.130.98.943.932.724.59.936.121.125.313.929.920.929.9-0.1

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-402500000.0-214500000.0-163800000.0-124100000.0-122700000.0-135200000.0-83200000.0-98600000.0-361800000.0-80700000.0-150600000.0-83000000.0-122000000.0-136400000.0-13200000.0-156700000.0-120400000.07500000.0-156800000.0-125200000.0-14000000.0-73200000.0-134000000.0-86400000.0-118100000.0-116100000.0-127400000.0-516900000.03100000.0-115100000.0-205900000.0-85300000.0-180500000.0-19700000.0-99900000.0-43500000.0-83200000.0-157600000.0-139900000.0-77300000.0-329100000.0-16100000.0-39700000.0-32800000.0
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 Revenues-132.0-70.5-54.5-40.2-34.4-37.5-23.1-31.1-101.5-23.1-43.1-27.2-34.6-37.9-3.8-49.6-33.32.1-43.7-37.4-3.7-19.0-36.7-27.0-29.4-29.2-34.8-180.40.9-32.6-60.8-31.3-54.4-5.7-29.1-15.3-25.2-46.6-44.5-29.2-107.4-5.2-13.8-12.4

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value9975-313.549358-222.83.318242-35.928-56.738-42.2-31.6-48.724-167.9-41.860-121.210-295.6177106-50.1-326.15317744-121.6148-161.4110102-91.11011495616292-53.8-191.5165
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 Revenues32.724.9-104.3159.816.5-61.80.957.611.9-10.38.2-18.610.9-11.7-9.1-15.46.7-46.3-11.618.1-32.02.8-80.955.426.6-12.6-89.1185.621.812.6-35.954.5-48.732.229.8-32.030.644.218.16.195.6-17.4-66.462.6

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

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value-541.0666-167.2-33.1-77.8419102-238.332147
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues-170.6218.0-54.8-10.9-25.9135.928.7-66.19.046.7

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DeferredIncomeTaxExpenseBenefit


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8.22.5-0.76.5167.04.71010.05.7-8.86.82.518-305.3141316-10.835222534151624181516118.5346.84.3-7.410.01110128.26.44.3-1.75.22.45.1
Percentage of DeferredIncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1341021465316512111164167134129771799317252193194161772221201355516311711651147124104241451128428119717936916486-0.3
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 Revenues44.233.848.717.246.433.631.020.346.938.537.125.350.825.949.416.553.353.545.023.258.731.237.117.540.829.531.917.941.435.130.98.943.932.724.59.936.121.125.313.929.920.929.9-0.1

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value5.53617473946564568414947387634249535730956169583945625851534253533527295323303132261919212118
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Revenues1.711.95.815.713.115.015.912.518.913.113.813.411.125.097.013.615.318.28.526.417.120.715.410.212.419.514.612.914.514.714.915.210.410.09.015.76.910.79.69.78.47.56.46.87.57.1

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-402500000.0-214500000.0-163800000.0-124100000.0-122700000.0-135200000.0-83200000.0-98600000.0-361800000.0-80700000.0-150600000.0-83000000.0-122000000.0-136400000.0-13200000.0-156700000.0-120400000.07500000.0-156800000.0-125200000.0-14000000.0-73200000.0-134000000.0-86400000.0-118100000.0-116100000.0-127400000.0-516900000.03100000.0-115100000.0-205900000.0-85300000.0-180500000.0-19700000.0-99900000.0-43500000.0-83200000.0-157600000.0-139900000.0-77300000.0-329100000.0-16100000.0-39700000.0-32800000.0
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 Revenues-132.0-70.5-54.5-40.2-34.4-37.5-23.1-31.1-101.5-23.1-43.1-27.2-34.6-37.9-3.8-49.6-33.32.1-43.7-37.4-3.7-19.0-36.7-27.0-29.4-29.2-34.8-180.40.9-32.6-60.8-31.3-54.4-5.7-29.1-15.3-25.2-46.6-44.5-29.2-107.4-5.2-13.8-12.4

Payments To Acquire Property Plant And Equipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value153509219249196194219191184147392169188178144127166129153120182140188171209445192190219141241137209151138137120693001044767
Percentage of PaymentsToAcquirePropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment gmt:AssetAcquisition, us-gaap:StatementBusinessSegments

gmt:RollsRoyceAircraftEngines, gmt:PortfolioManagement


Payments
Period End2021-03-31
Value-352.0
Percentage of PaymentsToAcquirePropertyPlantAndEquipment-69.1

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value9975-313.549358-222.83.318242-35.928-56.738-42.2-31.6-48.724-167.9-41.860-121.210-295.6177106-50.1-326.15317744-121.6148-161.4110102-91.11011495616292-53.8-191.5165
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 Revenues32.724.9-104.3159.816.5-61.80.957.611.9-10.38.2-18.610.9-11.7-9.1-15.46.7-46.3-11.618.1-32.02.8-80.955.426.6-12.6-89.1185.621.812.6-35.954.5-48.732.229.8-32.030.644.218.16.195.6-17.4-66.462.6

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:ProceedsFromIssuanceOfLongTermDebt


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302010-12-312010-09-30
Value-1.500000000000119210741201174868611930.2544953960.02970.0495-0.1-0.3297573411373220.0592166724699348423307412959713230247342441933140.0
Percentage of ProceedsFromIssuanceOfLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt


Repayments
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.00.07503500.02500.01603690.0251114010.01.43001.3442153202764.22643811361735830719743972643361956258355419526465.024151
Percentage of RepaymentsOfLongTermDebt0.00.0100.0100.00.0100.00.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Payments Of Dividends

us-gaap:PaymentsOfDividends

us-gaap:PaymentsOfDividends


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value18191717171916161719161717181616161816161618161617181414151614141516151414141313131413131313
Percentage of PaymentsOfDividends100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Effective Income Tax Rate Continuing Operations

us-gaap:EffectiveIncomeTaxRateContinuingOperations

us-gaap:EffectiveIncomeTaxRateContinuingOperations


Effective
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value2.722.2-0.050.3250.0240.01-0.010.24-0.0850.0100.25-1.4570.0200.3-0.017000.330.0600.020.33-0.0030.010.020.3-0.0380.1600.29-0.018-0.150.050.30.00200.020.23-0.0590.01
Percentage of EffectiveIncomeTaxRateContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.00.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

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

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1467000.01551000.01399000.01723000.01648000.01574000.01490000.01694000.01872000.01879000.01971000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap:AwardType

gmt:StockOptionSarAwards


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1313600.01179600.0963560.0756790.0459600.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber89.576.168.943.927.9

us-gaap:StockAppreciationRightsSARS


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value153370.0371720.0435550.0966120.01188600.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber10.524.031.156.172.1

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

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value63.5659.3255.7350.0746.7345.1839.6536.0333.8231.0830.47
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Liabilities

us-gaap:DeferredTaxLiabilities

us-gaap:DeferredTaxLiabilities


Deferred
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-31
Value96292491090889187789088187985311571134111010891104106710491018987974952937941930909891839807789783917865
Percentage of DeferredTaxLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Proceeds From Repayments Of Short Term Debt

us-gaap:ProceedsFromRepaymentsOfShortTermDebt

us-gaap:ProceedsFromRepaymentsOfShortTermDebt


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-2.0-3.29.57.0-19.69.5-96.6869.9-94.7110-4.30.2-0.1-11.4-0.412-0.8-1.1-23.5119.8-10.5141.0-69.113-80.310214-24.128-106.3-149.755114-72.7146-94.125-74.75844-34.1
Percentage of ProceedsFromRepaymentsOfShortTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:CashFlowHedgeGainLosstobeReclassifiedwithinTwelveMonthsGross

gmt:CashFlowHedgeGainLosstobeReclassifiedwithinTwelveMonthsGross


Cash
Period End2021-06-302021-03-312020-12-31
Value01800000.0-200000.0
Percentage of CashFlowHedgeGainLosstobeReclassifiedwithinTwelveMonthsGross0.0100.0100.0

gmt:CostofRepairsandMaintenance

gmt:CostofRepairsandMaintenance


Costof
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value7674768286767881
Percentage of CostofRepairsandMaintenance100.0100.0100.0100.0100.0100.0100.0100.0

gmt:DisposalGroupIncludingDiscontinuedOperationExpense us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

gmt:DisposalGroupIncludingDiscontinuedOperationExpense

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.00.0179.1474950
Percentage of DisposalGroupIncludingDiscontinuedOperationExpense0.00.0100.0100.0100.0100.0100.0

gmt:DispositionGainsonOwnedAssets

gmt:DispositionGainsonOwnedAssets


Disposition
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value32160.08.04.526174.4269.73.96.74.2502.77.6122113115.12029175.137211.218212418115.8
Percentage of DispositionGainsonOwnedAssets100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:DispositionGainsonOwnedAssets us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Disposition
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.30.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of DispositionGainsonOwnedAssets0.90.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:PortfolioManagement


Disposition
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.00.00.10.00.00.00.00.00.00.00.00.00.00.01.80.00.0-0.32.12.4147.20.12.04.60.00.50.00.20.14.14.2
Percentage of DispositionGainsonOwnedAssets0.00.02.20.00.00.00.00.00.00.00.00.00.00.014.20.00.0-2.641.212.048.241.42.05.321.40.02.70.00.80.536.072.4

gmt:RailInternational


Disposition
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.40.30.20.00.00.10.00.00.00.00.00.00.00.00.10.00.00.00.00.00.00.00.00.00.00.00.00.60.00.30.00.00.0
Percentage of DispositionGainsonOwnedAssets1.20.02.50.00.00.60.00.00.00.00.00.00.00.01.30.00.00.00.00.00.00.00.00.00.00.00.03.20.01.20.00.00.0

gmt:RailNorthAmerica


Disposition
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value3116-0.37.84.426174.4269.73.96.74.2494.57.5102113113.01715105.035161.2172124187.31.6
Percentage of DispositionGainsonOwnedAssets97.8100.00.097.597.8100.099.4100.0100.0100.0100.0100.0100.099.8166.798.785.8100.0100.0102.658.888.051.858.698.094.778.6100.094.1100.098.099.564.027.6

gmt:EquityMethodInvestment.SummarizedFinancialData.NetIncome us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:EquityMethodInvestment.SummarizedFinancialData.NetIncome

gmt:RrpfJointVentures


Equity
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value1912212332202723
Percentage of EquityMethodInvestment.SummarizedFinancialData.NetIncome100.0100.0100.0100.0100.0100.0100.0100.0

gmt:EquityMethodInvestmentSummarizedFinancialInformation.Revenue. us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:EquityMethodInvestmentSummarizedFinancialInformation.Revenue.

gmt:AlphaPartnersLeasingLimitedDomain


Equity
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value9293112102104949594
Percentage of EquityMethodInvestmentSummarizedFinancialInformation.Revenue.100.0100.0100.0100.0100.0100.0100.0100.0

gmt:EquityMethodInvestmentSummarizedFinancialInformationExpenses us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:EquityMethodInvestmentSummarizedFinancialInformationExpenses

gmt:AlphaPartnersLeasingLimitedDomain


Equity
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value8887958886758171
Percentage of EquityMethodInvestmentSummarizedFinancialInformationExpenses100.0100.0100.0100.0100.0100.0100.0100.0

gmt:EquityMethodInvestmentSummarizedFinancialInformationGainsLosses us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:EquityMethodInvestmentSummarizedFinancialInformationGainsLosses

gmt:AlphaPartnersLeasingLimitedDomain


Equity
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value-19.5-9.0-10.0-15.9-22.3-6.8-19.6-6.7
Percentage of EquityMethodInvestmentSummarizedFinancialInformationGainsLosses100.0100.0100.0100.0100.0100.0100.0100.0

gmt:GainLossOnDispositionOfAssetsNet

gmt:GainLossOnDispositionOfAssetsNet


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value3422-0.68.96.027155.1328.90.3106.156-2.29.42224-24.862362329-4.58.745246.328282523191621111828
Percentage of GainLossOnDispositionOfAssetsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:GainLossOnDispositionOfAssetsNet us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Gain
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.30.10.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of GainLossOnDispositionOfAssetsNet0.90.40.00.00.00.00.00.00.00.00.00.0-0.00.00.00.0-0.00.00.00.00.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:PortfolioManagement


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.50.60.60.50.60.5-5.80.50.30.3-4.20.20.30.3-3.40.3100.3-4.649313.916-16.51.53.65.31.11.71.30.41.78.15.34.41.12.611
Percentage of GainLossOnDispositionOfAssetsNet1.42.7-100.05.610.01.8-38.29.80.93.4-1400.01.94.90.5154.53.247.71.218.578.386.416.856.2366.717.27.921.517.56.04.61.67.241.331.720.19.714.239.6

gmt:RailInternational


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.80.30.40.50.20.10.50.30.50.4-3.40.51.11.60.51.00.80.8-0.40.50.30.70.30.51.14.90.20.82.62.4-0.11.31.31.2-1.41.01.20.9
Percentage of GainLossOnDispositionOfAssetsNet2.31.3-66.75.63.30.43.35.91.54.5-1133.34.918.02.9-22.710.63.63.21.60.80.83.01.0-11.112.610.80.812.79.28.5-0.45.56.67.2-6.48.86.63.2

gmt:RailNorthAmerica


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value3321-1.67.95.22610.04.3328.27.99.64.7542.68.11023-19.8134.71812116.136194.4232426201010189.21416
Percentage of GainLossOnDispositionOfAssetsNet95.495.6266.788.886.797.865.884.397.692.12633.393.277.096.4-118.286.248.695.679.820.912.780.243.1-255.670.181.278.069.884.888.3103.987.252.061.186.381.479.257.1

gmt:GatxOperatingLeaseOtherIncome

gmt:GatxOperatingLeaseOtherIncome


Gatx
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value1816222322222023
Percentage of GatxOperatingLeaseOtherIncome100.0100.0100.0100.0100.0100.0100.0100.0

gmt:IncomeLossFromEquityMethodInvestmentBeforeTax

gmt:IncomeLossFromEquityMethodInvestmentBeforeTax


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value139.02.646222340151918131416171516121120157.81023-1.512111917171425312212-1.719-1.35.5
Percentage of IncomeLossFromEquityMethodInvestmentBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:IncomeLossFromEquityMethodInvestmentBeforeTax us-gaap:StatementBusinessSegments

gmt:PortfolioManagement


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value139.02.746222340151918121415171816121119157.71023-1.612111817131023141210-2.114137.5
Percentage of IncomeLossFromEquityMethodInvestmentBeforeTax100.0100.0103.8100.0100.0100.0100.0100.0100.0100.099.298.698.899.4117.899.499.299.199.0100.798.799.0100.0106.7100.099.198.9100.076.377.392.247.052.684.0123.577.5-1015.4136.4

gmt:MarineOperatingExpense

gmt:MarineOperatingExpense


Marine
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value5.54.68.83.63.210403941124139371241383812403937124148471863645415575857167351497.75350398.94343356.4
Percentage of MarineOperatingExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:MarineOperatingExpense us-gaap:StatementBusinessSegments

gmt:PortfolioManagement


Marine
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value5.54.68.83.63.24.16.93.44.04.63.94.44.24.35.64.27.47.67.97.77.89.4111113121212121111119.56.85.55.25.65.8
Percentage of MarineOperatingExpense100.0100.0100.0100.0100.039.417.18.69.838.09.411.211.234.413.610.819.558.919.519.620.976.428.424.327.963.519.119.422.577.319.518.916.541.07.510.111.375.3

gmt:MarineOperatingRevenue

gmt:MarineOperatingRevenue


Marine
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value5.13.64.05.03.31158626013656055145862
Percentage of MarineOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:MarineOperatingRevenue us-gaap:StatementBusinessSegments

gmt:PortfolioManagement


Marine
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value5.13.64.05.03.33.33.81.90.12.43.33.13.54.43.23.8
Percentage of MarineOperatingRevenue100.0100.0100.0100.0100.028.06.53.00.218.35.15.16.331.05.56.0

gmt:NonoperatingIncomeResidualSharingIncome

gmt:NonoperatingIncomeResidualSharingIncome


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value1.00.70.70.60.60.60.50.60.40.40.80.70.60.40.40.58.90.40.449311.82.47.61.61.81.41.25.01.81.01.84.13.9
Percentage of NonoperatingIncomeResidualSharingIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:NonoperatingIncomeResidualSharingIncome us-gaap:StatementBusinessSegments

gmt:PortfolioManagement


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.50.60.60.50.50.50.40.50.30.30.30.20.30.30.30.38.70.30.349311.52.37.31.41.60.71.11.21.20.81.54.01.1
Percentage of NonoperatingIncomeResidualSharingIncome50.085.785.783.383.383.380.083.375.075.037.528.650.075.075.060.097.875.075.099.499.783.395.896.187.588.950.091.724.066.780.083.397.628.2

gmt:RailNorthAmerica


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.50.10.10.10.10.10.10.10.10.10.50.50.30.10.10.20.20.10.10.30.10.30.10.30.20.20.70.13.80.60.20.30.12.8
Percentage of NonoperatingIncomeResidualSharingIncome50.014.314.316.716.716.720.016.725.025.062.571.450.025.025.040.02.225.025.00.60.316.74.23.912.511.150.08.376.033.320.016.72.471.8

gmt:NonremarketingDispositionGainLoss

gmt:NonremarketingDispositionGainLoss


Nonremarketing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value1.55.5-1.00.30.9-0.13.60.15.7-1.24.62.91.35.71.41.32.33.4-1.51.41.91.40.11.62.05.72.64.04.45.03.93.75.27.9
Percentage of NonremarketingDispositionGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:NonremarketingDispositionGainLoss us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Nonremarketing
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.00.10.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of NonremarketingDispositionGainLoss0.01.80.0-0.00.00.00.0-0.00.00.00.00.00.00.00.00.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:RailInternational


Nonremarketing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value0.40.30.10.30.20.10.40.30.50.40.50.51.11.60.80.90.80.80.20.50.30.70.50.61.15.00.40.92.02.40.91.52.41.4
Percentage of NonremarketingDispositionGainLoss26.75.5-10.0100.022.2-100.011.1300.08.8-33.310.917.284.628.157.169.234.823.5-13.335.715.850.0500.037.555.087.715.422.545.548.023.140.546.217.7

gmt:RailNorthAmerica


Nonremarketing
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value1.15.1-1.10.00.7-0.2-7.3-0.25.2-1.64.12.40.24.10.70.41.52.6-1.70.91.60.7-0.31.00.90.72.33.12.42.63.02.22.86.5
Percentage of NonremarketingDispositionGainLoss73.392.7110.00.077.8200.0-202.8-200.091.2133.389.182.815.471.950.030.865.276.5113.364.384.250.0-300.062.545.012.388.577.554.552.076.959.553.882.3

gmt:OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIbeforeTax

gmt:OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIbeforeTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value-4.10.8-14.0-7.81.816-8.58.3
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentfromAOCIbeforeTax100.0100.0100.0100.0100.0100.0100.0100.0

gmt:PaymentsForAssetAcquisition gmt:AssetAcquisition, us-gaap:RelatedPartyTransactionsByRelatedParty, us-gaap:StatementBusinessSegments

gmt:PaymentsForAssetAcquisition

gmt:RollsRoyceAircraftEngines, gmt:RrpfJointVentures, gmt:PortfolioManagement


Payments
Period End2021-01-31
Value120
Percentage of PaymentsForAssetAcquisition100.0

gmt:PaymentsForAssetAcquisition gmt:AssetAcquisition, us-gaap:SubsequentEventType

gmt:RollsRoyceAircraftEngines, us-gaap:SubsequentEvent


Payments
Period End2021-01-31
Value120
Percentage of PaymentsForAssetAcquisition100.0

gmt:PortfolioInvestmentsandCapitalAdditions

gmt:PortfolioInvestmentsandCapitalAdditions


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value153509422249210194219191184147406169188178144163166129178120182140216142175180203171209445
Percentage of PortfolioInvestmentsandCapitalAdditions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:PortfolioInvestmentsandCapitalAdditions us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value6.23.52030.51.00.52.10.91.20.7210.20.80.70.60.10.10.20.31.21.80.60.60.71.80.40.81.11.81.9
Percentage of PortfolioInvestmentsandCapitalAdditions4.00.748.20.20.50.31.00.50.70.55.30.10.40.40.40.10.10.20.21.01.00.40.30.51.00.20.40.60.90.4

gmt:PortfolioManagement


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value0.53520.20.00.00.30.00.00.00.0140.00.00.00.0360.00.0250.00.00.0161.90.30.0155.0120.0
Percentage of PortfolioInvestmentsandCapitalAdditions0.369.20.00.00.00.20.00.00.00.03.50.00.00.00.022.40.00.014.00.00.00.07.51.30.20.07.52.95.70.0

gmt:RailInternational


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value404451454969575173334840342916223318231030223740274136454239
Percentage of PortfolioInvestmentsandCapitalAdditions26.58.712.218.123.735.626.027.140.022.511.923.818.316.511.214.019.914.513.49.016.715.717.528.815.922.917.926.620.28.8

gmt:RailNorthAmerica


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value1061091672041591101591381059932212914913612710312710212810814511216197135129149118145396
Percentage of PortfolioInvestmentsandCapitalAdditions69.121.439.681.775.857.072.972.357.267.279.376.179.176.588.163.176.779.772.490.079.980.574.768.877.171.873.569.369.688.9

gmt:PortfolioProceeds

gmt:PortfolioProceeds


Portfolio
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value7747103026636452924135492512334315544534625981848634176824471669811810364283312997263-30.2-122.243139-13.0
Percentage of PortfolioProceeds100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:PresentValueOfDividends

gmt:PresentValueOfDividends


Present
Period End2021-06-302021-03-312020-12-31
Value08.610
Percentage of PresentValueOfDividends0.0100.00.0

gmt:ProvisionForIncomeTaxesEquityMethodInvestment

gmt:ProvisionForIncomeTaxesEquityMethodInvestment


Provision
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value451.80.5244.84.38.03.03.53.51.82.70.03.26.32.72.73.01.7-0.11.42.7-3.7-2.83.03.04.14.65.44.226-3.79.34.16.0-0.50.02.4
Percentage of ProvisionForIncomeTaxesEquityMethodInvestment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0

gmt:SegmentProfitLoss

gmt:SegmentProfitLoss


Segment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value111937212689105130104132999510997145931161181247618413014115510111313713912112310312612399807690778186827362555958
Percentage of SegmentProfitLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:SegmentProfitLoss us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Segment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-5.20.22.81.60.6-0.4-0.80.81.11.5-3.6-0.50.82.4-1.80.90.73.1-0.91.7-0.30.8-0.12.3-3.4-5.2-1.0-0.6-2.1-3.3-0.60.1-0.7-1.5-1.0-1.5-0.5-1.1-2.1-0.8-1.0-0.90.80.55.0
Percentage of SegmentProfitLoss-4.60.23.91.30.7-0.4-0.60.80.81.5-3.8-0.50.81.7-1.90.80.62.5-1.20.9-0.20.6-0.12.3-3.0-3.8-0.7-0.5-1.7-3.2-0.50.1-0.7-1.9-1.3-1.7-0.6-1.3-2.4-1.0-1.4-1.41.50.88.6

gmt:PortfolioManagement


Segment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value126.1-5.7441919271011124.49.011139.01219141764361840-17.310152816111126171712-1.415142216118.810
Percentage of SegmentProfitLoss10.96.5-7.935.221.518.421.110.29.012.44.68.211.79.69.711.016.711.923.134.728.013.126.4-17.19.111.520.113.79.311.521.314.317.415.5-1.816.618.827.019.314.012.017.2

gmt:RailInternational


Segment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value272125242013221921141620121918201613142313121315192118191920193424181017-3.67.9
Percentage of SegmentProfitLoss24.423.235.519.022.213.117.619.116.114.916.818.913.213.120.117.314.010.818.412.610.08.98.815.316.815.813.516.215.720.115.528.224.623.013.819.8-4.69.7

gmt:RailNorthAmerica


Segment
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value7765495650726160856866686410861707493488776108989084105837091757557485059455350
Percentage of SegmentProfitLoss69.370.068.644.555.668.047.058.364.968.769.562.466.075.165.760.563.275.063.347.659.076.863.788.874.676.759.858.174.272.759.646.948.562.378.650.668.562.1

gmt:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPaymentRate

gmt:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPaymentRate


Share
Period End2021-06-302021-03-312020-12-31
Value00.50
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPaymentRate0.0100.00.0

us-gaap:CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths

us-gaap:CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths


Cash
Period End2021-06-302021-03-312020-12-31
Value01300000.0-200000.0
Percentage of CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths0.0100.0100.0

us-gaap:CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations


Cash
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value0.00.06.615-44.8-23.4
Percentage of CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations0.00.0100.0100.0100.0100.0

us-gaap:CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations


Cash
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value0.02.6252-13.726-0.3
Percentage of CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations0.0100.0100.0100.0100.0100.0

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations

us-gaap:CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations


Cash
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value0.00.0-7.1-1.41723
Percentage of CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations0.00.0100.0100.0100.0100.0

us-gaap:ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1 us-gaap:DerivativeInstrumentRisk, us-gaap:IncomeStatementLocation

us-gaap:ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1

us-gaap:InterestRateContract, us-gaap:InterestExpense


Change
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-1100000.0-1300000.0-1200000.0-1300000.0-200000.06900000.0-800000.01300000.05300000.03200000.05600000.0-1000000.0-1800000.0-5800000.0
Percentage of ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1 us-gaap:DerivativeInstrumentRisk, us-gaap:IncomeStatementLocation

us-gaap:ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1

us-gaap:InterestRateContract, us-gaap:InterestExpense


Change
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1100000.01300000.01200000.01300000.0200000.0-6900000.0800000.0-1300000.0-5300000.0-3200000.0-5600000.01000000.01800000.05800000.0
Percentage of ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CostOfPropertyRepairsAndMaintenance

us-gaap:CostOfPropertyRepairsAndMaintenance


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value76747076828687848581817782818084847787798678838380789485847376767466726867606868706968656567
Percentage of CostOfPropertyRepairsAndMaintenance100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CostOfPropertyRepairsAndMaintenance us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Cost
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.90.50.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of CostOfPropertyRepairsAndMaintenance1.20.70.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:RailInternational


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value141512131112111211121010111210119.710.011101212119.99.48.91111111110109.611129.81212
Percentage of CostOfPropertyRepairsAndMaintenance18.520.717.717.614.514.912.614.513.114.913.213.013.715.412.813.111.412.812.713.414.915.913.611.811.711.412.512.913.815.714.314.212.917.216.514.318.220.6

gmt:RailNorthAmerica


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value6158586370726864676861606468626668677062676564666369736565615758575453514848
Percentage of CostOfPropertyRepairsAndMaintenance80.378.682.382.485.584.277.775.878.284.776.378.278.283.977.877.980.786.980.278.978.283.877.179.579.688.477.776.877.584.075.476.277.581.973.274.872.279.1

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value0100000.0100000.0100000.0200000.0000100000.000000100000.00100000.0100000.0100000.00
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses0.0100.0100.0100.0100.00.00.00.0100.00.00.00.00.00.0100.00.0100.0100.0100.00.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value-3200000.0-3400000.0-3200000.0-3100000.0-3300000.0-3100000.0-1900000.0-2000000.0-2100000.0-1900000.0-2400000.0-2500000.0-2600000.0-2500000.0-2400000.0-2200000.0-2400000.0-2300000.0-2800000.0-2600000.0
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses0.0-3400.0-3200.0-3100.0-1650.00.00.00.0-2100.00.00.00.00.00.0-2400.00.0-2400.0-2300.0-2800.00.0

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302020-12-312020-09-302020-06-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value-100000.0-100000.00-100000.0-100000.00-100000.00100000.0-100000.0-100000.00-100000.00-100000.000-100000.0
Percentage of DefinedBenefitPlanAmortizationOfPriorServiceCostCredit100.0100.00.0100.0100.00.0100.00.0100.0100.0100.00.0100.00.0100.00.00.0100.0

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value4.64.75.35.05.05.15.45.65.55.55.55.65.55.66.15.96.06.06.16.5
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanInterestCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanInterestCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value0.00.10.10.10.20.10.20.20.30.20.30.20.30.20.40.20.30.20.20.2
Percentage of DefinedBenefitPlanInterestCost0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value2.02.03.13.13.03.13.83.83.83.83.63.73.73.73.93.83.93.83.53.9
Percentage of DefinedBenefitPlanInterestCost0.02000.03100.03100.01500.03100.01900.01900.01266.71900.01200.01850.01233.31850.0975.01900.01300.01900.01750.01950.0

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value0.00.00.00.10.20.20.20.20.40.20.20.30.30.20.20.10.10.2
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost0.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value2.82.93.13.23.33.11.91.91.91.92.64.73.02.51.91.72.11.71.97.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost0.00.00.00.00.03100.0950.0950.0950.0950.0650.02350.01500.0833.3633.3850.01050.01700.01900.03500.0

us-gaap:DefinedBenefitPlanServiceCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanServiceCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value100000.0100000.00100000.00100000.00100000.000100000.00100000.0100000.00100000.000100000.0
Percentage of DefinedBenefitPlanServiceCost100.0100.00.0100.00.0100.00.0100.00.00.0100.00.0100.0100.00.0100.00.00.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value2200000.02200000.02100000.02000000.02000000.02000000.01600000.01700000.01500000.01700000.02100000.02000000.02200000.01900000.01600000.01600000.01700000.01600000.01600000.01500000.0
Percentage of DefinedBenefitPlanServiceCost2200.00.02100.00.02000.00.01600.00.01500.00.00.02000.00.01900.01600.00.01700.00.00.01500.0

us-gaap:Depreciation

us-gaap:Depreciation


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value95928886848387868682848685818482807579797872757877718571715871656360646362586260605558575754
Percentage of Depreciation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DepreciationNonproduction

us-gaap:DepreciationNonproduction


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value91888583818084838379818181777978777276757569727574686171716268656357616059555957575255545551
Percentage of DepreciationNonproduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DepreciationNonproduction us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Depreciation
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value2.91.90.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of DepreciationNonproduction3.22.10.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:PortfolioManagement


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value5.02.71.31.31.41.31.71.61.71.61.81.81.91.81.81.71.81.71.81.71.81.71.84.75.45.55.75.85.85.55.95.85.85.55.55.65.25.4
Percentage of DepreciationNonproduction5.53.01.51.61.71.62.01.92.02.02.22.22.32.32.32.22.32.42.42.22.42.52.56.37.38.09.38.18.28.98.68.89.29.58.99.28.79.7

gmt:RailInternational


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value1818181715151514141413131314131211111111111111111010111111111110101010.08.98.68.6
Percentage of DepreciationNonproduction20.120.721.420.519.419.317.817.316.917.516.916.917.018.216.516.315.315.614.815.315.216.015.314.814.515.619.016.616.618.817.116.516.817.416.314.714.515.4

gmt:RailNorthAmerica


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value6565656564636463646462626161606059595858585655545352494949414644424242424141
Percentage of DepreciationNonproduction71.374.277.177.978.979.176.076.476.880.576.776.676.279.576.376.577.281.977.276.976.681.575.872.771.676.480.769.169.166.868.468.467.773.168.369.570.374.9

us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship, us-gaap:IncomeStatementLocation

us-gaap:DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet

us-gaap:ForeignExchangeContract, us-gaap:CashFlowHedging, us-gaap:OtherNonoperatingIncomeExpense


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.54.7-3.3-10.4-4.45.3-10.119-5.9111.42.216-8.2
Percentage of DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestRateContract, us-gaap:CashFlowHedging, us-gaap:InterestExpense


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.5-0.6-0.7-0.6-0.4-0.4-0.5-0.5-0.7-0.8-0.9-1.1-1.1-1.1
Percentage of DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet100.0-12.821.25.89.1-7.55.0-2.611.9-7.3-64.3-50.0-6.713.4

us-gaap:DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet us-gaap:IncomeStatementLocation

us-gaap:DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet

us-gaap:OtherNonoperatingIncomeExpense


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-3700000.02000000.01600000.02200000.0-4500000.06900000.0-3000000.04000000.0-1900000.0-800000.0-500000.0-3000000.05000000.0700000.0
Percentage of DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DirectFinancingLeaseLeaseIncome

us-gaap:DirectFinancingLeaseLeaseIncome


Direct
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value1600000.01700000.02300000.01500000.01600000.01800000.02100000.02200000.02700000.02800000.0
Percentage of DirectFinancingLeaseLeaseIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax


Discontinued
Period End2020-09-302020-06-302019-06-30
Value-300000.03600000.00
Percentage of DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax100.0100.00.0

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Discontinued
Period End2020-12-312020-09-302020-06-302019-06-30
Value0-300000.03600000.00
Percentage of DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax0.0100.0100.00.0

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerBasicShare

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerBasicShare


Discontinued
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value-0.010.06-0.020.410.230.210.01
Percentage of DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerBasicShare100.0100.0100.0100.0100.0100.0100.0

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare

us-gaap:DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare


Discontinued
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value-0.010.06-0.020.410.220.210.01
Percentage of DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare100.0100.0100.0100.0100.0100.0100.0

us-gaap:DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Discontinued
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.00.0-1.7-1.1171010.0
Percentage of DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax0.00.0100.0100.0100.0100.0100.0

us-gaap:DiscontinuedOperationTaxEffectOfDiscontinuedOperation us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationTaxEffectOfDiscontinuedOperation

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Discontinued
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value00-400000.0-200000.02700000.02400000.02300000.0
Percentage of DiscontinuedOperationTaxEffectOfDiscontinuedOperation0.00.0100.0100.0100.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312020-09-302020-06-302019-12-312019-09-302019-06-30
Value0.00.01.73.53.63.5
Percentage of DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization0.00.0100.0100.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value00800000.02000000.02200000.01800000.02100000.0
Percentage of DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense0.00.0100.0100.0100.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationInterestExpense us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationInterestExpense

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312019-12-312019-09-30
Value01500000.01600000.0
Percentage of DisposalGroupIncludingDiscontinuedOperationInterestExpense0.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationOperatingExpense us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationOperatingExpense

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.00.0157.1424444
Percentage of DisposalGroupIncludingDiscontinuedOperationOperatingExpense0.00.0100.0100.0100.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationOtherExpense us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationOtherExpense

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-09-302020-06-302020-03-312019-09-302019-06-30
Value01500000.01500000.01700000.01800000.0
Percentage of DisposalGroupIncludingDiscontinuedOperationOtherExpense0.0100.0100.0100.0100.0

us-gaap:DisposalGroupIncludingDiscontinuedOperationRevenue us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DisposalGroupIncludingDiscontinuedOperationRevenue

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Disposal
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.00.0179.5566161
Percentage of DisposalGroupIncludingDiscontinuedOperationRevenue0.00.0100.0100.0100.0100.0100.0

us-gaap:DividendsCommonStockCash us-gaap:StatementEquityComponents

us-gaap:DividendsCommonStockCash

us-gaap:RetainedEarnings


Dividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312015-03-31
Value181817171717161717171717171768
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EffectOfExchangeRateOnCashAndCashEquivalents

us-gaap:EffectOfExchangeRateOnCashAndCashEquivalents


Effect
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1600000.0-1800000.0900000.0200000.01600000.0-2800000.0700000.0-1600000.0700000.0-300000.0200000.0-500000.0-3900000.0200000.0900000.0200000.01600000.01300000.0-1000000.0200000.0-1400000.01000000.0-700000.0-600000.01100000.0-5000000.0-1900000.0-1900000.0100000.01000000.0500000.0400000.0-1600000.0-400000.0-100000.0-200000.0400000.0-1000000.0-3400000.01800000.0-200000.0-300000.0-300000.0-400000.0400000.0100000.0
Percentage of EffectOfExchangeRateOnCashAndCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense

us-gaap:EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense


Employee
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value1000000.01500000.01500000.01000000.0900000.0500000.01400000.01000000.01100000.01300000.0900000.01400000.01200000.01200000.01400000.01300000.01500000.01200000.02500000.01300000.01100000.01100000.01000000.01100000.01200000.01100000.01800000.01200000.01200000.01200000.01300000.01200000.01200000.01200000.01200000.01100000.01200000.01100000.01500000.0800000.0900000.01000000.0
Percentage of EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnDispositionOfAssets

us-gaap:GainLossOnDispositionOfAssets


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
Value3321-1.08.35.426214.5328.68.59.85.4554.18.9152411127.02130197.043245.12326282116139.410.01724182115148.412
Percentage of GainLossOnDispositionOfAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnSalesOfAssetsAndAssetImpairmentCharges

us-gaap:GainLossOnSalesOfAssetsAndAssetImpairmentCharges


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value3422-0.68.96.027155.1328.90.3106.156-2.29.422-24.9-24.862362329-4.58.745246.328282523191621111828
Percentage of GainLossOnSalesOfAssetsAndAssetImpairmentCharges100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTax

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTax


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value0.0-0.32.3-0.9147.97.70.3
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTax0.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTax us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.0-0.32.3-0.9147.97.7
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTax0.0100.0100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity


Income
Period End2020-09-302020-06-302020-03-312019-09-302019-06-30
Value0.0-1.3-0.97.97.7
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity0.0100.0100.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity us-gaap:DisposalGroupClassification, us-gaap:IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperations

us-gaap:DiscontinuedOperationsDisposedOfBySale, gmt:Asc


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value0.00.0-1.3-0.9147.97.7
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity0.00.0100.0100.00.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare


Income
Period End2020-09-302020-06-302020-03-312019-09-302019-06-30
Value-0.010.06-0.020.230.21
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare

us-gaap:IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare


Income
Period End2020-09-302020-06-302020-03-312019-09-302019-06-30
Value-0.010.06-0.020.220.21
Percentage of IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromEquityMethodInvestments

us-gaap:IncomeLossFromEquityMethodInvestments


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-31.67.22.1221719321216141111131413129.78.718156.47.5271.39.08.51412129.91835138.4-3.719-1.35.56.71.815177.55.76.618
Percentage of IncomeLossFromEquityMethodInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-31.77.22.12217195.4121614-23.8111214-8.33.79.68.7-16.8156.47.4-4.91.38.88.5-0.37.34.4-1.9-3.5342.57.9-28.315-0.7-2.0-16.81.110.0170.13.2-16.214
Percentage of IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements


Incremental
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value600000.0700000.0-100000.0400000.0500000.0500000.00600000.0700000.0600000.00800000.0700000.0600000.00600000.0500000.0500000.0-100000.0500000.0500000.0400000.0100000.0600000.0700000.0700000.00800000.0800000.0800000.00600000.0600000.0700000.0100000.0600000.0600000.0700000.0100000.0600000.0700000.0600000.00400000.0400000.0
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0

us-gaap:LeaseIncome

us-gaap:LeaseIncome


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value287280274273269271272271274274271271271273274276274272279281
Percentage of LeaseIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LeaseIncome us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Lease
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value6.13.60.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of LeaseIncome2.11.30.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

gmt:PortfolioManagement


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value8.33.30.20.10.20.30.20.30.20.30.20.30.20.30.70.71.21.21.21.2
Percentage of LeaseIncome2.91.20.10.00.10.10.10.10.10.10.10.10.10.10.30.30.40.40.40.4

gmt:RailInternational


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value6966666459585755535252525252505046434546
Percentage of LeaseIncome24.023.824.323.621.921.521.120.519.719.019.319.219.319.218.418.216.915.916.216.5

gmt:RailNorthAmerica


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value204206207208210212214214218220218218217219222224225227232233
Percentage of LeaseIncome71.073.775.776.478.078.178.479.079.980.580.380.380.380.381.081.282.383.383.082.7

us-gaap:NetCashProvidedByUsedInDiscontinuedOperations

us-gaap:NetCashProvidedByUsedInDiscontinuedOperations


Net
Period End2020-12-312020-09-302020-06-302020-03-31
Value0.02.62510.1
Percentage of NetCashProvidedByUsedInDiscontinuedOperations0.0100.0100.0100.0

us-gaap:NetCashProvidedByUsedInFinancingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInFinancingActivitiesContinuingOperations


Net
Period End2021-06-302021-03-312020-06-302020-03-31
Value-602.41038-298.3478
Percentage of NetCashProvidedByUsedInFinancingActivitiesContinuingOperations100.0100.0100.0100.0

us-gaap:NetCashProvidedByUsedInInvestingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInInvestingActivitiesContinuingOperations


Net
Period End2021-06-302021-03-312020-06-302020-03-31
Value-63500000.0-446800000.0-177500000.0-110400000.0
Percentage of NetCashProvidedByUsedInInvestingActivitiesContinuingOperations100.0100.0100.0100.0

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations

us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations


Net
Period End2021-06-302021-03-312020-06-302020-03-31
Value1227614454
Percentage of NetCashProvidedByUsedInOperatingActivitiesContinuingOperations100.0100.0100.0100.0

us-gaap:OperatingLeaseLeaseIncome

us-gaap:OperatingLeaseLeaseIncome


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value286278271271267269266269271271
Percentage of OperatingLeaseLeaseIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingLeaseLeaseIncomeLeasePayments

us-gaap:OperatingLeaseLeaseIncomeLeasePayments


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value268262256258252255251254253253
Percentage of OperatingLeaseLeaseIncomeLeasePayments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingLeaseVariableLeaseIncome

us-gaap:OperatingLeaseVariableLeaseIncome


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value17161513151415141717
Percentage of OperatingLeaseVariableLeaseIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingLeasesRentExpenseNet

us-gaap:OperatingLeasesRentExpenseNet


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value101011121213131313131211121315151515191918162122222027272726323133323332323132313334353534
Percentage of OperatingLeasesRentExpenseNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingLeasesRentExpenseNet us-gaap:StatementBusinessSegments

gmt:RailNorthAmerica


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value1010111212131313131312111213151514151717161620202020252525263029323232313131
Percentage of OperatingLeasesRentExpenseNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.098.198.197.494.989.589.689.7100.092.792.492.4100.094.193.494.1100.095.094.395.2100.096.496.096.3100.0

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax


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
Value15-36.6251919-39.622-33.611-10.5-7.3-4.7-50.41419154017-42.211-20.725-16.4-2.911-48.0-29.8-48.1-1.90.71232-2.5-17.01610-27.425-22.7-56.41920-0.244-57.3
Percentage of OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax

us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value15-36.61919-39.6-33.611-10.5-4.7-50.41415401711-20.725-2.911-48.0-48.1-1.90.732-2.5-17.0
Percentage of OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossBeforeTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value14-31.89.211-35.9-15.96.82.42.7-32.43.44.92212-2.3-22.32.8-2.0-2.0-42.0-47.9-1.8-2.0521.9-16.2
Percentage of OtherComprehensiveIncomeLossBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-1.04.1-4.0-11.0-4.84.9-10.618-6.6100.51.015-9.3
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax us-gaap:IncomeStatementLocation

us-gaap:InterestExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.5-0.6-0.7-0.6-0.4-0.4-0.5-0.5-0.7-0.8-0.9-1.1-1.1-1.1
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax50.0-14.617.55.58.3-8.24.7-2.710.6-7.8-180.0-110.0-7.211.8

us-gaap:OtherNonoperatingIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-0.54.7-3.3-10.4-4.45.3-10.119-5.9111.42.216-8.2
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax50.0114.682.594.591.7108.295.3102.789.4107.8280.0220.0107.288.2

us-gaap:OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship

us-gaap:OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax

us-gaap:ForeignExchangeContract, us-gaap:CashFlowHedging


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.9-4.84.9108.5-3.97.4-18.2-0.2-0.1-4.2-2.70.0-0.7
Percentage of OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0

us-gaap:InterestRateContract, us-gaap:CashFlowHedging


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
Value0.00.0-0.4-0.1-1.11.64.4130.00.0-17.2-10.8
Percentage of OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax0.00.0-4.72.6-14.9-8.8-2200.0-13000.0-0.0-0.00.01542.9

us-gaap:OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship

us-gaap:CashFlowHedging


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-06-302018-03-31
Value0.9-4.84.9108.1-3.97.9-18.24.212-17.2-11.5
Percentage of OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax100.0100.0100.0100.095.3100.0106.8100.0-2100.0-12900.00.01642.9

us-gaap:OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax

us-gaap:OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax


Other
Period End2021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value100000.0100000.0-800000.0-300000.0-100000.0600000.0700000.0200000.0600000.0-700000.0600000.0800000.0-100000.01800000.0-2100000.0-1700000.01100000.0700000.01600000.01200000.0700000.0700000.0-4300000.0-1500000.0-700000.0
Percentage of OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value18-33.52219-38.125-33.214-5.5-6.82.2-46.31519174420-20.06.8-24.024-16.91.413-48.5-63.2-45.80.72.659514.3-13.4-2.012-15.329-51.2-56.71830
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax


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-2.3-2.51.8-2.3-3.5-2.2-1.3-1.4-1.5-3.01.7-5.3-1.9-1.90.6-1.4-1.4-1.3-16.16.01.3-1.4-1.5-2.1-2.1-2.134-1.6-1.7-1.4-46.5-2.1-2.3-2.016-1.41.3-1.421-0.90.8
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax


Other
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value0.11.2-0.20.00.00.04.60.00.00.00.00.0-11.90.00.00.00.00.00.00.00.00.00.00.0
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax100.0100.0100.00.00.00.0100.00.00.00.00.00.0100.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value-0.8-0.8-0.8-0.7-0.7-0.6-0.41.1-1.7-0.6-0.6-0.8-0.8-0.93.6-0.7-0.9-1.2-1.4-1.2-0.9-0.9-1.01.31.31.3
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value1.0-4.1114.8-4.9-18.86.6-10.2-1.0-15.29.311215.85.7-4.9192.314-7.01.61.53.6-1.7-1.6-1.6
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value3.13.33.03.03.12.01.91.92.42.52.52.22.22.22.32.02.33.33.53.32.52.62.4-3.4-3.6-3.3
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossTax

us-gaap:OtherComprehensiveIncomeLossTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value0.80.90.9-0.10.40.51.0-0.41.91.2-0.11.41.60.8-1.1-1.2-0.82.22.02.82.01.61.4-6.0-2.8-2.1
Percentage of OtherComprehensiveIncomeLossTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value-0.64.8-10.6-8.93.917-4.9122.818-11.5-10.5-18.4-5.1-3.4-2.0-23.21.3-13.36.00.40.0-2.2184.30.6
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax

us-gaap:OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax


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
Value0.40.6-0.80.3-3.3-0.71.8-1.01.12.02.21.62.2-1.51.20.72.10.87.40.5-4.8-2.5-1.82.50.1-2.60.70.80.80.71.1154.41.5-1.90.2112.2-7.3-1.0-1.08.81.00.0-5.4
Percentage of OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherCostAndExpenseOperating


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
Value11109.38.39.28.57.87.77.88.06.98.59.18.68.58.57.89.61010148.8158.37.87.37.68.06.76.66.96.97.05.3-15.4161310168.21211
Percentage of OtherCostAndExpenseOperating100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherCostAndExpenseOperating us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Other
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.90.40.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of OtherCostAndExpenseOperating7.93.90.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.00.00.00.0

gmt:PortfolioManagement


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value0.40.20.20.10.10.10.30.10.10.1-0.40.10.10.20.30.10.30.3-0.50.34.10.55.30.40.50.90.30.70.50.40.70.70.60.41.60.30.6-1.6
Percentage of OtherCostAndExpenseOperating3.52.02.21.21.11.23.81.31.31.2-5.81.21.12.33.51.23.83.1-5.03.027.75.735.34.86.412.33.98.87.56.110.110.18.67.5-10.41.94.5-15.5

gmt:RailInternational


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value1.72.02.61.61.51.82.61.41.31.51.51.31.51.51.21.11.21.21.51.21.21.41.61.11.50.91.51.21.01.41.71.31.40.91.11.11.81.1
Percentage of OtherCostAndExpenseOperating14.919.628.019.316.321.233.318.216.718.821.715.316.517.414.112.915.412.514.911.98.115.910.713.319.212.319.715.014.921.224.618.820.017.0-7.16.813.610.7

gmt:RailNorthAmerica


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value8.47.66.56.67.66.64.96.26.46.45.87.17.56.97.07.36.38.19.18.69.56.98.16.85.85.55.86.15.24.84.54.95.04.04.95.24.04.4
Percentage of OtherCostAndExpenseOperating73.774.569.979.582.677.662.880.582.180.084.183.582.480.282.485.980.884.490.185.164.278.454.081.974.475.376.376.277.672.765.271.071.475.5-31.832.330.342.7

us-gaap:OtherNoncashIncomeExpense

us-gaap:OtherNoncashIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-15.225-7.77.3-30.437-20.12.94.7422.0-7.2-19.216-24.744-46.030-7.9-14.20.92811-34.0130.4-8.8-30.022-3.4100.518-33.9-2.2-18.2
Percentage of OtherNoncashIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherOperatingIncome

us-gaap:OtherOperatingIncome


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value24212627252624
Percentage of OtherOperatingIncome100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherOperatingIncome us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Other
Period End2021-06-302021-03-312020-06-302019-06-30
Value2.31.10.00.0
Percentage of OtherOperatingIncome9.45.10.00.0

gmt:PortfolioManagement


Other
Period End2021-06-302021-03-312020-09-302020-06-302019-09-302019-06-30
Value0.20.20.10.30.10.3
Percentage of OtherOperatingIncome0.80.90.41.10.41.2

gmt:RailInternational


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value2.72.52.62.11.82.41.8
Percentage of OtherOperatingIncome11.111.610.07.57.19.17.3

gmt:RailNorthAmerica


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value19172325232322
Percentage of OtherOperatingIncome78.782.489.791.492.990.591.4

us-gaap:PaymentsForProceedsFromOtherInvestingActivities

us-gaap:PaymentsForProceedsFromOtherInvestingActivities


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-03-31
Value0.5-0.4-0.7-0.1-0.9-0.3-1.70.5-0.8-0.7-0.4-0.1-0.1-2.5-0.60.7-0.50.00.00.00.00.00.00.00.0-9.70.0-5.80.00.00.00.10.0
Percentage of PaymentsForProceedsFromOtherInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.00.00.00.00.00.0100.00.0100.00.00.00.0100.00.0

us-gaap:PaymentsToAcquireBusinessesGross us-gaap:BusinessAcquisition

us-gaap:PaymentsToAcquireBusinessesGross

gmt:TrifleetLeasingHoldingBV


Payments
Period End2020-12-29
Value165
Percentage of PaymentsToAcquireBusinessesGross100.0

us-gaap:ProceedsFromDivestitureOfBusinesses

us-gaap:ProceedsFromDivestitureOfBusinesses


Proceeds
Period End2020-12-312020-09-30
Value0.00.7
Percentage of ProceedsFromDivestitureOfBusinesses0.0100.0

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value3.320-13.20.4-13.3-0.2113.40.4-0.70.8-2.2-0.1-1.30.2-0.1-0.4-2.313-1.6-0.3-1.65.6-1.42.22.91.0-1.3-0.3-1.21.6-0.5-0.31.4-1.21.3
Percentage of ProceedsFromPaymentsForOtherFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleOfOtherProductiveAssets

us-gaap:ProceedsFromSaleOfOtherProductiveAssets


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
Value13158.54.76.16.74.14.38.16.58.87.6128.86.09.47.37.64.44.44.89.42.53.34.38.64.26.49.37.07.96.49.38.75.95.87.59.210109.9118.57.4
Percentage of ProceedsFromSaleOfOtherProductiveAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RepaymentsOfLongTermCapitalLeaseObligations

us-gaap:RepaymentsOfLongTermCapitalLeaseObligations


Repayments
Period End2021-06-302021-03-312020-06-302020-03-312013-12-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.0330.07.90.10.01.20.71.10.01.1161.48.41.51.51.4
Percentage of RepaymentsOfLongTermCapitalLeaseObligations0.0100.00.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate


Share
Period End2021-06-302021-03-312020-12-31
Value02.20
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate0.0100.00.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate


Share
Period End2021-06-302021-03-312020-12-31
Value034.40
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate0.0100.00.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate


Share
Period End2021-06-302021-03-312020-12-31
Value00.30
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate0.0100.00.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross


Share
Period End2021-06-302021-03-31
Value5300.0276600.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross100.0100.0

us-gaap:StockIssuedDuringPeriodSharesNewIssues us-gaap:StatementEquityComponents

us-gaap:StockIssuedDuringPeriodSharesNewIssues

us-gaap:CommonStock


Stock
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312015-03-31
Value100000.0300000.0100000.00100000.0100000.000100000.0100000.000100000.0100000.0200000.0
Percentage of StockIssuedDuringPeriodSharesNewIssues100.0100.0100.00.0100.0100.00.00.0100.0100.00.00.0100.0100.0100.0

dei:EntityCommonStockSharesOutstanding

dei:EntityCommonStockSharesOutstanding


Entity
Period End2021-06-302021-03-312020-09-30
Value353535
Percentage of EntityCommonStockSharesOutstanding100.0100.0100.0

dei:EntityPublicFloat

dei:EntityPublicFloat


Entity
Period End2020-12-31
Value2100
Percentage of EntityPublicFloat100.0

gmt:AmountOfSecuredDebtAvailableToBeBorrowedInAccordanceWithPublicDebtCovenants

gmt:AmountOfSecuredDebtAvailableToBeBorrowedInAccordanceWithPublicDebtCovenants


Amount
Period End2020-12-31
Value1717
Percentage of AmountOfSecuredDebtAvailableToBeBorrowedInAccordanceWithPublicDebtCovenants100.0

gmt:AssetsOfContinuingOperations

gmt:AssetsOfContinuingOperations


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-312018-12-31
Value9400991589378690851279947318
Percentage of AssetsOfContinuingOperations100.0100.0100.0100.0100.0100.0100.0

gmt:AssetsOfContinuingOperations us-gaap:StatementBusinessSegments

gmt:OtherBusinessSegments


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-31
Value6731217435487504206
Percentage of AssetsOfContinuingOperations7.212.34.95.65.92.6

gmt:PortfolioManagement


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-312018-12-31
Value10391067706709676653606
Percentage of AssetsOfContinuingOperations11.110.87.98.27.98.28.3

gmt:RailInternational


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-31
Value173116981851165415731486
Percentage of AssetsOfContinuingOperations18.417.120.719.018.518.6

gmt:RailNorthAmerica


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-31
Value595559325944583857585646
Percentage of AssetsOfContinuingOperations63.359.866.567.267.670.6

gmt:AssetsOfContinuingOperations us-gaap:StatementGeographical

gmt:Domestic


Assets
Period End2020-12-312019-12-312018-12-31
Value549953694848
Percentage of AssetsOfContinuingOperations61.567.266.2

gmt:Foreign


Assets
Period End2020-12-312019-12-312018-12-31
Value343826242470
Percentage of AssetsOfContinuingOperations38.532.833.8

gmt:DebtAdjustmentForFairValueHedges

gmt:DebtAdjustmentForFairValueHedges


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value-5.6-1.47.54.7-0.6-1.5-0.6-5.4-10.21517
Percentage of DebtAdjustmentForFairValueHedges100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:DeferredTaxAssetsOperatingLeaseLiability

gmt:DeferredTaxAssetsOperatingLeaseLiability


Deferred
Period End2020-12-312019-12-31
Value95108
Percentage of DeferredTaxAssetsOperatingLeaseLiability100.0100.0

gmt:DeferredTaxAssetsValuationOnStateNetOperatingLoss

gmt:DeferredTaxAssetsValuationOnStateNetOperatingLoss


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1312121012121111121515
Percentage of DeferredTaxAssetsValuationOnStateNetOperatingLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:DeferredTaxLiabilitiesRightofUseAssets

gmt:DeferredTaxLiabilitiesRightofUseAssets


Deferred
Period End2020-12-312019-12-31
Value93103
Percentage of DeferredTaxLiabilitiesRightofUseAssets100.0100.0

gmt:DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation

gmt:DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees

us-gaap:Cash, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1.00.0120.0010.0010.001
Percentage of DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees100.0100.0100.0100.0100.0

us-gaap:DebtSecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value62.80.6510.6490.5680.454
Percentage of DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees6280.05425.064900.056800.045400.0

us-gaap:EquitySecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value33.70.3050.3030.3940.486
Percentage of DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees3370.02541.730300.039400.048600.0

us-gaap:RealEstate, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value2.50.0320.0470.0370.059
Percentage of DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees250.0266.74700.03700.05900.0

gmt:DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees us-gaap:RetirementPlanSponsorLocation

country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value100.01.01.01.01.0
Percentage of DefinedBenefitPlanActualPlanAssetAllocationsHourlyEmployees10000.08333.3100000.0100000.0100000.0

gmt:DefinedBenefitPlanAmountsRecognizedinBalanceSheetandAccumulatedOtherComprehensiveIncomeLoss us-gaap:RetirementPlanType

gmt:DefinedBenefitPlanAmountsRecognizedinBalanceSheetandAccumulatedOtherComprehensiveIncomeLoss

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-26.9-28.9-31.1-32.5-35.0
Percentage of DefinedBenefitPlanAmountsRecognizedinBalanceSheetandAccumulatedOtherComprehensiveIncomeLoss100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value6675818793
Percentage of DefinedBenefitPlanAmountsRecognizedinBalanceSheetandAccumulatedOtherComprehensiveIncomeLoss-248.3-262.3-261.4-270.5-266.0

gmt:DefinedBenefitPlanEstimatedFutureBenefitPayments gmt:DefinedBenefitPlans

gmt:DefinedBenefitPlanEstimatedFutureBenefitPayments

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value36332839343226
Percentage of DefinedBenefitPlanEstimatedFutureBenefitPayments100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value16192327232830
Percentage of DefinedBenefitPlanEstimatedFutureBenefitPayments46.458.081.969.668.285.6113.4

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value282285275281278300296
Percentage of DefinedBenefitPlanEstimatedFutureBenefitPayments785.6857.7961.3719.7804.3918.01101.1

gmt:DefinedBenefitPlanPensionPlanswithAccumulatedBenefitObligationsinExcessofPlanAssetsAggregateProjectedFairValueofPlanAssets

gmt:DefinedBenefitPlanPensionPlanswithAccumulatedBenefitObligationsinExcessofPlanAssetsAggregateProjectedFairValueofPlanAssets


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value32130025529937837845640
Percentage of DefinedBenefitPlanPensionPlanswithAccumulatedBenefitObligationsinExcessofPlanAssetsAggregateProjectedFairValueofPlanAssets100.0100.0100.0100.0100.0100.0100.0100.0

gmt:DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation

gmt:DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage

us-gaap:DebtSecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value43.00.510.510.455
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage100.0100.0100.0100.0

us-gaap:EquitySecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value53.00.4560.4560.507
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage123.389.489.4111.4

us-gaap:RealEstate, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value4.00.0340.0340.038
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage9.36.76.78.4

gmt:DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage us-gaap:RetirementPlanSponsorLocation

country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value100.01.01.01.0
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationSalariedEmployeesPercentage232.6196.1196.1219.8

gmt:DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation

gmt:DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees

us-gaap:Cash, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1.10.0150.0020.0080.011
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees100.0100.0100.0100.0100.0

us-gaap:DebtSecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value41.40.4850.5180.4480.412
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees3763.63233.325900.05600.03745.5

us-gaap:EquitySecurities, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value54.60.4660.4410.5070.531
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees4963.63106.722050.06337.54827.3

us-gaap:RealEstate, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value2.90.0340.0390.0370.046
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees263.6226.71950.0462.5418.2

gmt:DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees us-gaap:RetirementPlanSponsorLocation

country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value100.01.01.01.01.0
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocationsSalariedEmployees9090.96666.750000.012500.09090.9

gmt:DirectFinanceLeaseReceivablesNetOfDeferredIncome

gmt:DirectFinanceLeaseReceivablesNetOfDeferredIncome


Direct
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value667374636466909395118126129130133136139141144147158161166167170177175174188190200207213222239245241241274334347
Percentage of DirectFinanceLeaseReceivablesNetOfDeferredIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:LeaseLiability

gmt:LeaseLiability


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value34232838136840439944044046546711
Percentage of LeaseLiability100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:LeaseRightofUseAsset

gmt:LeaseRightofUseAsset


Lease
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value33532637336440240242243045746616
Percentage of LeaseRightofUseAsset100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:LeasesFutureMinimumPaymentsReceivable

gmt:LeasesFutureMinimumPaymentsReceivable


Leases
Period End2020-12-31
Value2995
Percentage of LeasesFutureMinimumPaymentsReceivable100.0

gmt:LeasesFutureMinimumPaymentsReceivableCurrent

gmt:LeasesFutureMinimumPaymentsReceivableCurrent


Leases
Period End2020-12-31
Value941
Percentage of LeasesFutureMinimumPaymentsReceivableCurrent100.0

gmt:LeasesFutureMinimumPaymentsReceivableInFiveYears

gmt:LeasesFutureMinimumPaymentsReceivableInFiveYears


Leases
Period End2020-12-31
Value198
Percentage of LeasesFutureMinimumPaymentsReceivableInFiveYears100.0

gmt:LeasesFutureMinimumPaymentsReceivableInFourYears

gmt:LeasesFutureMinimumPaymentsReceivableInFourYears


Leases
Period End2020-12-31
Value367
Percentage of LeasesFutureMinimumPaymentsReceivableInFourYears100.0

gmt:LeasesFutureMinimumPaymentsReceivableInThreeYears

gmt:LeasesFutureMinimumPaymentsReceivableInThreeYears


Leases
Period End2020-12-31
Value533
Percentage of LeasesFutureMinimumPaymentsReceivableInThreeYears100.0

gmt:LeasesFutureMinimumPaymentsReceivableInTwoYears

gmt:LeasesFutureMinimumPaymentsReceivableInTwoYears


Leases
Period End2020-12-31
Value724
Percentage of LeasesFutureMinimumPaymentsReceivableInTwoYears100.0

gmt:LeasesFutureMinimumPaymentsReceivableThereafter

gmt:LeasesFutureMinimumPaymentsReceivableThereafter


Leases
Period End2020-12-31
Value230
Percentage of LeasesFutureMinimumPaymentsReceivableThereafter100.0

gmt:LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments

gmt:LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments


Lessee
Period End2020-12-312019-12-31
Value6179
Percentage of LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments100.0100.0

gmt:LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments gmt:OperatingLeasesByType

gmt:RecourseOperatingLeases


Lessee
Period End2020-12-312019-12-31
Value6179
Percentage of LesseeOperatingLeasesFutureMinimumPaymentsInterestIncludedInPayments100.0100.0

gmt:NumberofAircraftEnginesUnderLeasingArrangement us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:NumberofAircraftEnginesUnderLeasingArrangement

gmt:RrpfJointVentures


Numberof
Period End2020-12-31
Value215.0
Percentage of NumberofAircraftEnginesUnderLeasingArrangement100.0

gmt:OfficeFurnitureFixturesAndOtherEquipmentNet

gmt:OfficeFurnitureFixturesAndOtherEquipmentNet


Office
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3235342027313434353233
Percentage of OfficeFurnitureFixturesAndOtherEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:OperatingandFinanceLeasesFutureMinimumPaymentsDueNextTwelveMonths

gmt:OperatingandFinanceLeasesFutureMinimumPaymentsDueNextTwelveMonths


Operatingand
Period End2020-12-31
Value83
Percentage of OperatingandFinanceLeasesFutureMinimumPaymentsDueNextTwelveMonths100.0

gmt:OtherAssetsCurrentAndNonCurrent

gmt:OtherAssetsCurrentAndNonCurrent


Other
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value8487848084848457505260
Percentage of OtherAssetsCurrentAndNonCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossNetActuarialLossGainRecognized us-gaap:RetirementPlanType

gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossNetActuarialLossGainRecognized

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value3.03.12.2-2.82.9
Percentage of PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossNetActuarialLossGainRecognized100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-109.9-118.5-125.2-132.5-144.1
Percentage of PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossNetActuarialLossGainRecognized-3663.3-3822.6-5690.94732.1-4969.0

gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossPriorServiceCreditCostRecognized us-gaap:RetirementPlanType

gmt:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossPriorServiceCreditCostRecognized

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-1000000.0-1200000.0-1400000.0-1600000.0-1800000.0
Percentage of PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossPriorServiceCreditCostRecognized100.0100.0100.0100.0100.0

gmt:RecourseDebt

gmt:RecourseDebt


Recourse
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value58036374532951835047504347804580483247684429439743974359437142664261425042534204429843044171427142084443417940814033431037653621354634833152334733283141335431452990281028012553
Percentage of RecourseDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:RecourseFixedRateDebtFairValueDisclosure us-gaap:FairValueByMeasurementBasis

gmt:RecourseFixedRateDebtFairValueDisclosure

us-gaap:CarryingReportedAmountFairValueDisclosure


Recourse
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302012-12-31
Value528057245056478846584153438941934441443639333998399939563971386438623857385838683721372339153996399040683639340834133718287126842343
Percentage of RecourseFixedRateDebtFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Recourse
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value573461115696529549634354464444684631447038363935395239704089397739533902385239963944370238824017402242193775355535732994
Percentage of RecourseFixedRateDebtFairValueDisclosure108.6106.8112.7110.6106.5104.8105.8106.6104.3100.897.598.498.8100.4103.0102.9102.4101.299.8103.3106.099.499.2100.5100.8103.7103.7104.3104.7104.3

gmt:RecourseFloatingRateDebtFairValueDisclosure us-gaap:FairValueByMeasurementBasis

gmt:RecourseFloatingRateDebtFairValueDisclosure

us-gaap:CarryingReportedAmountFairValueDisclosure


Recourse
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302012-12-31
Value550683299422417915417414419361522423424427426425422418417360600600275275217375540673620591894937809
Percentage of RecourseFloatingRateDebtFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Recourse
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value550684300419413911419415416359515425423428428429424417412352581567264265216376540679624906
Percentage of RecourseFloatingRateDebtFairValueDisclosure100.1100.0100.299.298.999.6100.4100.299.599.698.5100.399.7100.1100.6101.0100.499.898.797.896.994.596.196.599.6100.2100.0100.9100.7101.3

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value165143147139145120149138152155177152162141154133196143174146152144170148171163165172205171159197167151177158137132135150137126114123
Percentage of AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Accounts
Period End2020-12-312019-12-31
Value11096
Percentage of AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent74.964.5

us-gaap:AccountsReceivableGrossCurrent

us-gaap:AccountsReceivableGrossCurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value83817470717687939779878584718383766785851057169907664868188548081836688858460767876637168
Percentage of AccountsReceivableGrossCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccrualForEnvironmentalLossContingencies

us-gaap:AccrualForEnvironmentalLossContingencies


Accrual
Period End2020-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value10131314131314151619
Percentage of AccrualForEnvironmentalLossContingencies100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value-13600000.0-14000000.0-14600000.0-13800000.0-14100000.0-10800000.0-10100000.0-11900000.0-10900000.0-12000000.0-14000000.0-16200000.0-17800000.0-20000000.0-15500000.0-16700000.0-17400000.0-19500000.0-20300000.0-27700000.0-28200000.0-23400000.0-20900000.0-19100000.0-21600000.0-21700000.0-19100000.0-19800000.0-20600000.0-21400000.0-22100000.0-23200000.0-38600000.0-43000000.0-44500000.0-56200000.0-55700000.0-52200000.0-47400000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value7476797779838586888992909698838384858710397989910110310510773757678124126129131-118.7-99.9-105.0-92.3
Percentage of AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-3.0-3.2-2.80.9-2.9
Percentage of AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax-3.8-3.7-3.01.1-3.3

us-gaap:PensionPlansDefinedBenefit


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value8288958290
Percentage of AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax103.8103.7103.098.9103.3

us-gaap:AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value-65.0-80.3-43.7-69.0-88.7-107.7-68.1-90.4-56.8-68.5-58.0-50.7-46.04.4-10.5-29.7-45.1-85.8-103.7-61.5-72.5-51.8-77.7-61.3-58.4-69.9-21.97.9565757441114316.4467456
Percentage of AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure

us-gaap:AssetsHeldForSaleLongLivedFairValueDisclosure


Assets
Period End2020-12-312019-12-312018-12-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-12-31
Value4.83.41.34.5232172896265701061757.0
Percentage of AssetsHeldForSaleLongLivedFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetsNet us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName, us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:AssetsNet

gmt:RrpfJointVentures, us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value47665015
Percentage of AssetsNet100.0100.0

us-gaap:BusinessAcquisitionCostOfAcquiredEntityTransactionCosts us-gaap:BusinessAcquisition

us-gaap:BusinessAcquisitionCostOfAcquiredEntityTransactionCosts

gmt:TrifleetLeasingHoldingBV


Business
Period End2020-12-29
Value2700000.0
Percentage of BusinessAcquisitionCostOfAcquiredEntityTransactionCosts100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet

gmt:TrifleetLeasingHoldingBV


Business
Period End2020-12-29
Value146
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet100.0

us-gaap:CapitalLeasedAssetsGross us-gaap:PropertyPlantAndEquipmentByType

us-gaap:CapitalLeasedAssetsGross

gmt:Railcars


Capital
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value379.0191918170.0
Percentage of CapitalLeasedAssetsGross100.0100.0100.0100.0100.0100.00.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivable

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivable


Capital
Period End2020-12-31
Value77
Percentage of CapitalLeasesFutureMinimumPaymentsReceivable100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableCurrent

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableCurrent


Capital
Period End2020-12-31
Value16
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableCurrent100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueInRollingYearThree

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueInRollingYearThree


Capital
Period End2020-12-31
Value8400000.0
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableDueInRollingYearThree100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueThereafter

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableDueThereafter


Capital
Period End2020-12-31
Value15
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableDueThereafter100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFiveYears

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFiveYears


Capital
Period End2020-12-31
Value5800000.0
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableInFiveYears100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFourYears

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInFourYears


Capital
Period End2020-12-31
Value9300000.0
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableInFourYears100.0

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInTwoYears

us-gaap:CapitalLeasesFutureMinimumPaymentsReceivableInTwoYears


Capital
Period End2020-12-31
Value21
Percentage of CapitalLeasesFutureMinimumPaymentsReceivableInTwoYears100.0

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation


Capital
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value0.30.12.41.661797571676788
Percentage of CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassOtherPropertyPlantAndEquipmentNet

us-gaap:CapitalLeasesLesseeBalanceSheetAssetsByMajorClassOtherPropertyPlantAndEquipmentNet


Capital
Period End2020-12-312019-12-312018-12-31
Value378.916
Percentage of CapitalLeasesLesseeBalanceSheetAssetsByMajorClassOtherPropertyPlantAndEquipmentNet100.0100.0100.0

us-gaap:CommonStockCapitalSharesReservedForFutureIssuance

us-gaap:CommonStockCapitalSharesReservedForFutureIssuance


Common
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value8300000.08500000.08800000.09000000.05600000.05800000.06000000.06300000.06600000.03300000.0
Percentage of CommonStockCapitalSharesReservedForFutureIssuance100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CommonStockCapitalSharesReservedForFutureIssuance us-gaap:StatementClassOfStock

gmt:Sharebasedcompensationawardplans


Common
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value2100000.02100000.02200000.02200000.02200000.02300000.02500000.02700000.0
Percentage of CommonStockCapitalSharesReservedForFutureIssuance25.324.725.024.439.339.741.742.9

us-gaap:StockCompensationPlan


Common
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value6200000.06400000.06600000.06800000.03400000.03500000.03500000.03500000.06500000.0
Percentage of CommonStockCapitalSharesReservedForFutureIssuance74.775.375.075.660.760.358.355.698.5

us-gaap:DebtInstrumentCarryingAmount

us-gaap:DebtInstrumentCarryingAmount


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value53294780442943714253417841953842328134983015
Percentage of DebtInstrumentCarryingAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtInstrumentCarryingAmount us-gaap:LongtermDebtType

gmt:RecourseFixedRateDebt


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value50584396395039863868392336472874225026152448
Percentage of DebtInstrumentCarryingAmount94.992.089.291.291.093.986.974.868.674.881.2

gmt:RecourseFixedRateDebtUnsecuredEight


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1221123002502508.120085100200200
Percentage of DebtInstrumentCarryingAmount2.32.36.85.75.90.24.82.23.05.76.6

gmt:RecourseFixedRateDebtUnsecuredEighteenMember


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value5001500.0300250300250250
Percentage of DebtInstrumentCarryingAmount9.43.10.06.95.97.26.06.5

gmt:RecourseFixedRateDebtUnsecuredEleven


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1228430050250250125050100100
Percentage of DebtInstrumentCarryingAmount2.31.86.81.15.96.00.31.31.52.93.3

gmt:RecourseFixedRateDebtUnsecuredFifteen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value300500250350300502502500.02223
Percentage of DebtInstrumentCarryingAmount5.610.55.68.07.11.26.06.50.00.60.8

gmt:RecourseFixedRateDebtUnsecuredFive


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value25025050605.32002002502502500.0
Percentage of DebtInstrumentCarryingAmount4.75.21.11.40.14.84.86.57.67.10.0

gmt:RecourseFixedRateDebtUnsecuredFour


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value122502503.010300250250250250250
Percentage of DebtInstrumentCarryingAmount2.31.05.60.10.27.26.06.57.67.18.3

gmt:RecourseFixedRateDebtUnsecuredFourteen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3003003003002502502502500.02728
Percentage of DebtInstrumentCarryingAmount5.66.36.86.95.96.06.06.50.00.80.9

gmt:RecourseFixedRateDebtUnsecuredNine


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value12230030010025054250100100115130
Percentage of DebtInstrumentCarryingAmount2.36.36.82.35.91.36.02.63.03.34.3

gmt:RecourseFixedRateDebtUnsecuredNineteen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3000.00.02501503003000.00.00.21.0
Percentage of DebtInstrumentCarryingAmount5.60.00.05.73.57.27.20.00.00.00.0

gmt:RecourseFixedRateDebtUnsecuredOne


Debt
Period End2020-12-312019-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value250250300200100300300300300
Percentage of DebtInstrumentCarryingAmount4.75.27.14.82.47.89.18.69.9

gmt:RecourseFixedRateDebtUnsecuredSeven


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value12830025025030010300200200200200
Percentage of DebtInstrumentCarryingAmount2.46.35.65.77.10.37.25.26.15.76.6

gmt:RecourseFixedRateDebtUnsecuredSeventeenMemberDomain


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value5002500.0300300250250250
Percentage of DebtInstrumentCarryingAmount9.45.20.06.97.16.06.06.5

gmt:RecourseFixedRateDebtUnsecuredSix


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value30025025030052250100200200200200
Percentage of DebtInstrumentCarryingAmount5.65.25.66.91.26.02.45.26.15.76.6

gmt:RecourseFixedRateDebtUnsecuredSixteen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value300300150300350250503000.02021
Percentage of DebtInstrumentCarryingAmount5.66.33.46.98.26.01.27.80.00.60.7

gmt:RecourseFixedRateDebtUnsecuredTen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value300350350250100300151001001000.0
Percentage of DebtInstrumentCarryingAmount5.67.37.95.72.47.20.42.63.02.90.0

gmt:RecourseFixedRateDebtUnsecuredThirteen


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value9130030025025010025017194041
Percentage of DebtInstrumentCarryingAmount1.76.36.85.75.92.46.00.40.61.21.4

gmt:RecourseFixedRateDebtUnsecuredThree


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2502501001225010070250250250250
Percentage of DebtInstrumentCarryingAmount4.75.22.30.35.92.41.76.57.67.18.3

gmt:RecourseFixedRateDebtUnsecuredTwelve


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value350300300250502503002221500.0
Percentage of DebtInstrumentCarryingAmount6.66.36.85.71.26.07.20.60.61.40.0

gmt:RecourseFixedRateDebtUnsecuredTwenty


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2502500.01500.02500.0340.00.0181
Percentage of DebtInstrumentCarryingAmount4.75.20.03.40.06.00.00.90.00.06.0

gmt:RecourseFixedRateDebtUnsecuredTwentyOne


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312011-12-312010-12-31
Value1501500.00.00.00.01000.018
Percentage of DebtInstrumentCarryingAmount2.83.10.00.00.00.02.40.00.6

gmt:RecourseFixedRateDebtUnsecuredTwo


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value50100250250200250250250250300300
Percentage of DebtInstrumentCarryingAmount0.92.15.65.74.76.06.06.57.68.69.9

gmt:RecourseFloatingRateDebt


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value300417523426417275540894896726342
Percentage of DebtInstrumentCarryingAmount5.68.711.89.79.86.612.923.327.320.811.4

us-gaap:DebtInstrumentUnamortizedDiscountPremiumNet

us-gaap:DebtInstrumentUnamortizedDiscountPremiumNet


Debt
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value-35.1-34.9-35.9-36.2-33.6-28.5-8.6-8.9-8.39.314
Percentage of DebtInstrumentUnamortizedDiscountPremiumNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtLongtermAndShorttermCombinedAmount

us-gaap:DebtLongtermAndShorttermCombinedAmount


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value58216394535251965053531947964692485847844540
Percentage of DebtLongtermAndShorttermCombinedAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsNet

us-gaap:DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsNet


Deferred
Period End2020-12-312019-12-312018-12-312017-12-31
Value3000000.02600000.03100000.03800000.0
Percentage of DeferredFinanceCostsOwnshareLendingArrangementIssuanceCostsNet100.0100.0100.0100.0

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredIncomeTaxLiabilities


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value11731114941931120011381074970904800785778765769760759750730
Percentage of DeferredIncomeTaxLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsGross


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value211190637811112013678121152
Percentage of DeferredTaxAssetsGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsDomestic

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsDomestic


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value53150.04.10.013418.90.03814
Percentage of DeferredTaxAssetsOperatingLossCarryforwardsDomestic100.0100.00.0100.00.0100.0100.0100.00.0100.0100.0

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsForeign

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsForeign


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2100000.02200000.02100000.02100000.02900000.03600000.05800000.08500000.09500000.07300000.04700000.0
Percentage of DeferredTaxAssetsOperatingLossCarryforwardsForeign100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3831262925272827263128
Percentage of DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsOther


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1.73.60.52.629129.87.6181415
Percentage of DeferredTaxAssetsOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsTaxCreditCarryforwardsForeign

us-gaap:DeferredTaxAssetsTaxCreditCarryforwardsForeign


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value0.80.80.20.00.05.83.63.67.31316
Percentage of DeferredTaxAssetsTaxCreditCarryforwardsForeign100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1616171930353213484031
Percentage of DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1623242126221814192120
Percentage of DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1100000.01200000.01100000.01100000.01500000.03200000.01700000.02200000.06600000.05400000.03900000.0
Percentage of DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates

us-gaap:DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2637364369729993818284
Percentage of DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxLiabilitiesLeasingArrangements

us-gaap:DeferredTaxLiabilitiesLeasingArrangements


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3339129.0117.31024121313
Percentage of DeferredTaxLiabilitiesLeasingArrangements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DeferredTaxLiabilitiesOther


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value2800000.03200000.01900000.06300000.01000000.00100000.003100000.02900000.01700000.0
Percentage of DeferredTaxLiabilitiesOther100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value101793089087211191058963852806756704
Percentage of DeferredTaxLiabilitiesPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value481450394457441
Percentage of DefinedBenefitPlanAccumulatedBenefitObligation100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-4.0-4.3-3.61.2-4.7
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value109118125132144
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax-2747.5-2755.8-3477.811033.3-3063.8

us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent

us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value16114.46.21.10.70.0320.0
Percentage of DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent100.0100.0100.0100.0100.0100.00.0100.00.0

us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate us-gaap:Range, us-gaap:PlanName, us-gaap:RetirementPlanSponsorLocation

us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate

srt:Maximum, gmt:SalariedUnfundedPlansDomain, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value2.35000
Percentage of DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate100.00.00.00.0

srt:Minimum, gmt:SalariedUnfundedPlansDomain, country:US


Defined
Period End2020-12-312019-12-312018-12-312017-12-31
Value1.19000
Percentage of DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate50.60.00.00.0

us-gaap:DefinedBenefitPlanBenefitObligation us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanBenefitObligation

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value222427333035
Percentage of DefinedBenefitPlanBenefitObligation100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value508475413480464475
Percentage of DefinedBenefitPlanBenefitObligation2221.01932.51504.41424.61532.71357.1

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value17161420191815
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value6.77.89.5119.91114
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter38.346.763.856.251.663.491.5

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value134141137142142144152
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter769.1846.1920.8702.0739.6789.6994.8

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value3.43.22.53.02.52.52.0
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value2.33.03.23.43.23.93.5
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths67.693.8128.0113.3128.0156.0175.0

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value30282827274228
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths891.2900.01132.0913.31080.01716.01410.0

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value3.83.53.04.43.63.52.8
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value1.71.92.42.82.32.63.1
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive44.754.380.063.663.974.3110.7

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value29292728272829
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive778.9854.3926.7638.6766.7817.11057.1

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value3.83.52.93.93.53.22.3
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value1.82.02.63.02.52.83.2
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour47.457.189.776.971.487.5139.1

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value29282728272829
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour786.8817.1948.3717.9785.7881.21269.6

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value3.83.32.63.93.22.62.3
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value2.02.22.83.22.73.33.3
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree52.666.7107.782.184.4126.9143.5

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value28282727272828
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree757.9860.61057.7710.3850.01080.81247.8

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo gmt:DefinedBenefitPlans

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo

gmt:NonqualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value3.73.12.83.62.62.62.2
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo100.0100.0100.0100.0100.0100.0100.0

gmt:OtherBenefits


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value2.22.43.03.43.03.83.4
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo59.577.4107.194.4115.4146.2154.5

gmt:QualifiedPlans


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value29282727272728
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo800.0922.6985.7769.41038.51073.11286.4

us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-31
Value5700000.0
Percentage of DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear100.0

us-gaap:DefinedBenefitPlanFairValueOfPlanAssets

us-gaap:DefinedBenefitPlanFairValueOfPlanAssets


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value465432369435413416457447409377
Percentage of DefinedBenefitPlanFairValueOfPlanAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanFairValueOfPlanAssets us-gaap:DefinedBenefitPlanByPlanAssetCategories

gmt:FixedIncomeCollectiveTrustFunds


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value226232207211151160208138131125120
Percentage of DefinedBenefitPlanFairValueOfPlanAssets48.553.756.048.436.638.545.530.832.133.20.0

gmt:ShortTermInvestmentFunds


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value4.65.90.72.63.11.60.91.31.04.34.0
Percentage of DefinedBenefitPlanFairValueOfPlanAssets1.01.40.20.60.70.40.20.30.21.10.0

gmt:StockCollectiveFunds


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value223181148204210190215263245222243
Percentage of DefinedBenefitPlanFairValueOfPlanAssets47.941.940.146.950.945.847.158.759.958.90.0

us-gaap:RealEstateInvestment


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1113131418201721211713
Percentage of DefinedBenefitPlanFairValueOfPlanAssets2.63.03.73.44.54.93.94.85.34.70.0

us-gaap:DefinedBenefitPlanFairValueOfPlanAssets us-gaap:RetirementPlanType

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value465432369435413416
Percentage of DefinedBenefitPlanFairValueOfPlanAssets100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanFundedStatusOfPlan us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanFundedStatusOfPlan

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-22.9-24.6-27.5-33.7-30.3
Percentage of DefinedBenefitPlanFundedStatusOfPlan100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value-43.1-42.7-43.9-44.5-50.9
Percentage of DefinedBenefitPlanFundedStatusOfPlan188.2173.6159.6132.0168.0

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value413730371264121706645340854
Percentage of DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation

us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value3803543033504304385026747342560
Percentage of DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage

us-gaap:DebtSecurities, us-gaap:ForeignPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-31
Value63.20.632
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationPercentage100.0100.0

us-gaap:EquitySecurities, us-gaap:ForeignPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-31
Value36.80.368
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationPercentage58.258.2

us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType

us-gaap:ForeignPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-31
Value100.01.0
Percentage of DefinedBenefitPlanPlanAssetsTargetAllocationPercentage158.2158.2

us-gaap:DefinedBenefitPlanWeightedAverageAssetAllocations us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanSponsorLocation, us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanWeightedAverageAssetAllocations

us-gaap:DebtSecurities, us-gaap:ForeignPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value69.30.6660.6660.640.623
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocations100.0100.0100.0100.0100.0

us-gaap:EquitySecurities, us-gaap:ForeignPlan, us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value30.70.3340.3340.360.377
Percentage of DefinedBenefitPlanWeightedAverageAssetAllocations44.350.250.256.260.5

us-gaap:DerivativeAssets

us-gaap:DerivativeAssets


Derivative
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312013-09-302012-12-312011-12-312010-12-31
Value6.48.54.91.21612116.0150101717
Percentage of DerivativeAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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

us-gaap:ForeignExchangeContract, us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value4.14.80.40.20.96.9106.19.94.4
Percentage of DerivativeAssets0.00.06.20.00.081.20.00.00.089.8

us-gaap:ForeignExchangeContract, us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value0.22.60.40.11.50.20.40.10.40.5
Percentage of DerivativeAssets0.00.06.20.00.02.40.00.00.010.2

us-gaap:InterestRateContract, us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value3.24.65.66.98.28.31.42.41.2
Percentage of DerivativeAssets0.00.087.50.00.00.016.50.00.0

us-gaap:DerivativeAssets us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation

us-gaap:ForeignExchangeContract, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value4.14.80.40.20.96.9106.19.94.4
Percentage of DerivativeAssets0.00.06.20.00.081.20.00.00.089.8

us-gaap:ForeignExchangeContract, us-gaap:FairValueMeasurementsRecurring, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value0.22.60.40.11.50.20.40.10.40.5
Percentage of DerivativeAssets0.00.06.20.00.02.40.00.00.010.2

us-gaap:InterestRateContract, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-30
Value3.24.65.66.98.28.31.42.41.2
Percentage of DerivativeAssets0.00.087.50.00.00.016.50.00.0

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

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value7.5126.46.98.5108.5137.4104.9
Percentage of DerivativeAssets0.00.0100.00.00.00.0100.00.00.00.0100.0

us-gaap:DerivativeAssets us-gaap:FairValueByMeasurementFrequency

us-gaap:FairValueMeasurementsRecurring


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value7.5126.46.98.5108.5137.4104.9
Percentage of DerivativeAssets0.00.0100.00.00.00.0100.00.00.00.0100.0

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

us-gaap:DerivativeLiabilities

us-gaap:ForeignExchangeContract, us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value9.03.12.17.01.99.98.518
Percentage of DerivativeLiabilities100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ForeignExchangeContract, us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring, us-gaap:Nondesignated


Derivative
Period End2021-06-302020-09-302020-06-302019-12-312019-09-302019-06-302019-03-312018-12-31
Value1.00.93.16.03.07.05.34.7
Percentage of DerivativeLiabilities0.010.0100.085.7157.970.762.425.8

us-gaap:DerivativeLiabilities us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementFrequency, us-gaap:HedgingDesignation

us-gaap:ForeignExchangeContract, us-gaap:FairValueMeasurementsRecurring, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value9.03.12.17.01.99.98.518
Percentage of DerivativeLiabilities100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ForeignExchangeContract, us-gaap:FairValueMeasurementsRecurring, us-gaap:Nondesignated


Derivative
Period End2021-06-302020-09-302020-06-302019-12-312019-09-302019-06-302019-03-312018-12-31
Value1.00.93.16.03.07.05.34.7
Percentage of DerivativeLiabilities0.010.0100.085.7157.970.762.425.8

us-gaap:DerivativeLiabilities us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:InterestRateContract, us-gaap:Nondesignated


Derivative
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value9.03.12.47.63.71013
Percentage of DerivativeLiabilities100.0100.0114.3108.6194.7103.0152.9

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

us-gaap:FairValueInputsLevel2, us-gaap:FairValueMeasurementsRecurring


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value1.09.96.22.4136.7171830
Percentage of DerivativeLiabilities0.0110.0200.0114.3194.3352.6173.7214.1168.1

us-gaap:DerivativeLiabilities us-gaap:FairValueByMeasurementFrequency

us-gaap:FairValueMeasurementsRecurring


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value1.09.96.22.4136.7171830
Percentage of DerivativeLiabilities0.0110.0200.0114.3194.3352.6173.7214.1168.1

us-gaap:DerivativeNotionalAmount us-gaap:DerivativeInstrumentRisk, us-gaap:DerivativeInstrumentsGainLossByHedgingRelationship, us-gaap:HedgingDesignation

us-gaap:DerivativeNotionalAmount

us-gaap:InterestRateContract, us-gaap:CashFlowHedging, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value305135105136242281336
Percentage of DerivativeNotionalAmount100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestRateContract, us-gaap:FairValueHedging, us-gaap:DesignatedAsHedgingInstrument


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value200300300300300300450
Percentage of DerivativeNotionalAmount65.6222.1283.8220.4123.6106.5133.7

us-gaap:DirectFinancingLeaseDeferredSellingProfit

us-gaap:DirectFinancingLeaseDeferredSellingProfit


Direct
Period End2020-12-312019-12-312018-12-31
Value273450
Percentage of DirectFinancingLeaseDeferredSellingProfit100.0100.0100.0

us-gaap:DirectFinancingLeaseLeaseReceivable

us-gaap:DirectFinancingLeaseLeaseReceivable


Direct
Period End2020-12-312019-12-312018-12-31
Value7784119
Percentage of DirectFinancingLeaseLeaseReceivable100.0100.0100.0

us-gaap:DirectFinancingLeaseNetInvestmentInLease

us-gaap:DirectFinancingLeaseNetInvestmentInLease


Direct
Period End2020-12-312019-12-312018-12-31
Value7490126
Percentage of DirectFinancingLeaseNetInvestmentInLease100.0100.0100.0

us-gaap:DirectFinancingLeaseUnguaranteedResidualAsset

us-gaap:DirectFinancingLeaseUnguaranteedResidualAsset


Direct
Period End2020-12-312019-12-312018-12-31
Value244057
Percentage of DirectFinancingLeaseUnguaranteedResidualAsset100.0100.0100.0

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized us-gaap:AwardType

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized

gmt:RestrictedStockAndPerformanceShareAwards


Employee
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value8.310108.49.06.37.96.56.6
Percentage of EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:StockOptionSarAwards


Employee
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value6.77.47.17.06.46.0146.26.3
Percentage of EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized80.771.868.383.371.195.2178.595.495.5

us-gaap:FinanceLeaseLiability

us-gaap:FinanceLeaseLiability


Finance
Period End2021-06-302020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value4333310.07.90.0101111
Percentage of FinanceLeaseLiability100.0100.0100.00.0100.00.0100.0100.0100.0

us-gaap:FinanceLeaseRightOfUseAsset

us-gaap:FinanceLeaseRightOfUseAsset


Finance
Period End2021-06-302020-12-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value4937300.08.90.0161616
Percentage of FinanceLeaseRightOfUseAsset100.0100.0100.00.0100.00.0100.0100.0100.0

us-gaap:FinanceLeaseWeightedAverageDiscountRatePercent

us-gaap:FinanceLeaseWeightedAverageDiscountRatePercent


Finance
Period End2020-12-312019-12-31
Value0.952.26
Percentage of FinanceLeaseWeightedAverageDiscountRatePercent100.0100.0

us-gaap:GuaranteeObligationsMaximumExposure

us-gaap:GuaranteeObligationsMaximumExposure


Guarantee
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value10.010.01010109.3119.410112021222216182023252728313234353739404249525996104130131133134142
Percentage of GuaranteeObligationsMaximumExposure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GuaranteeObligationsMaximumExposure us-gaap:DerivativeInstrumentRisk, us-gaap:GuaranteeObligationsByNature

gmt:RrpfJointVentures, us-gaap:Derivative


Guarantee
Period End2021-06-302021-03-312020-12-312020-09-302020-06-30
Value1.01.01.51.51.4
Percentage of GuaranteeObligationsMaximumExposure10.010.014.213.913.3

us-gaap:GuaranteeObligationsMaximumExposure us-gaap:GuaranteeObligationsByNature

us-gaap:FinancialStandbyLetterOfCredit


Guarantee
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value9.09.01.59.39.19.39.3119.49.49.5171718178.88.88.98.98.98.98.98.98.68.68.68.78.78.78.78.88.9159.89.79.69.69.69.810
Percentage of GuaranteeObligationsMaximumExposure90.090.014.286.186.70.0100.0100.0100.086.282.686.683.581.578.453.747.843.237.235.333.031.328.726.525.024.023.122.321.320.617.717.126.110.19.37.47.37.27.37.2

us-gaap:PropertyLeaseGuarantee


Guarantee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312010-12-31
Value9.10.00.00.01.52.02.73.54.24.97.69.61115161819222325262830313334363739414244454752
Percentage of GuaranteeObligationsMaximumExposure85.80.00.00.013.817.413.416.518.521.646.352.256.862.864.767.068.771.372.373.874.975.876.777.778.469.969.864.240.639.232.533.534.135.137.1

us-gaap:HedgedAssetFairValueHedgeCumulativeIncreaseDecrease us-gaap:BalanceSheetLocation

us-gaap:HedgedAssetFairValueHedgeCumulativeIncreaseDecrease

gmt:RecourseDebt


Hedged
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value5600000.01400000.02200000.0900000.0-4400000.0-7700000.0
Percentage of HedgedAssetFairValueHedgeCumulativeIncreaseDecrease100.0100.0100.0100.0100.0100.0

us-gaap:HedgedLiabilityFairValueHedge us-gaap:BalanceSheetLocation

us-gaap:HedgedLiabilityFairValueHedge

gmt:RecourseDebt


Hedged
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value202302303304305304449
Percentage of HedgedLiabilityFairValueHedge100.0100.0100.0100.0100.0100.0100.0

us-gaap:HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease us-gaap:BalanceSheetLocation

us-gaap:HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease

gmt:RecourseDebt


Hedged
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value3200000.04600000.05600000.06900000.08200000.08300000.01400000.0
Percentage of HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilityForAsbestosAndEnvironmentalClaimsNet

us-gaap:LiabilityForAsbestosAndEnvironmentalClaimsNet


Liability
Period End2020-12-312019-12-312018-12-31
Value101413
Percentage of LiabilityForAsbestosAndEnvironmentalClaimsNet100.0100.0100.0

us-gaap:LineOfCreditFacilityCapacityAvailableForTradePurchases us-gaap:LineOfCreditFacility

us-gaap:LineOfCreditFacilityCapacityAvailableForTradePurchases

us-gaap:ForeignLineOfCredit


Line
Period End2020-12-312019-12-31
Value7.320
Percentage of LineOfCreditFacilityCapacityAvailableForTradePurchases100.0100.0

us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity us-gaap:CreditFacility

us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity

gmt:DelayedDrawTermLoan


Line
Period End2020-12-31
Value500
Percentage of LineOfCreditFacilityMaximumBorrowingCapacity100.0

us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity us-gaap:LineOfCreditFacility

gmt:LineOfCreditUs


Line
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312013-12-312012-12-312011-12-31
Value600600600600600575575560560
Percentage of LineOfCreditFacilityMaximumBorrowingCapacity120.00.00.00.00.00.00.00.00.0

us-gaap:LitigationReserve

us-gaap:LitigationReserve


Litigation
Period End2020-12-31
Value5400000.0
Percentage of LitigationReserve100.0

us-gaap:LoansAndLeasesReceivableAllowance

us-gaap:LoansAndLeasesReceivableAllowance


Loans
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value6.56.46.56.26.16.26.26.06.06.16.46.56.56.66.46.55.75.76.1141410106.36.05.65.75.45.65.25.24.74.54.34.63.43.13.0111111111113
Percentage of LoansAndLeasesReceivableAllowance100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LoansAndLeasesReceivableNetReportedAmount

us-gaap:LoansAndLeasesReceivableNetReportedAmount


Loans
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value143148142127130137171180187192207207209198213215212205227237259234235264260247352364393370404410326335356351351362430415411385407365
Percentage of LoansAndLeasesReceivableNetReportedAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value3041283427102360201014801239866
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value199521891330894943904888288
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive65.677.249.137.947.061.171.633.3

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value600350250336302529433485
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value2034327323896182776764
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths33.9123.5292.8115.7204.352.315.513.2

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value544529250250557592514236
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value210168274310265426100245
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive38.731.7109.8124.047.671.919.5104.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value550250250566350507427626
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value293381425584470106245359
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour53.3152.6170.2103.3134.521.157.557.4

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value250250663350550455660552
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value38934228649454252450622
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree155.9137.043.1141.39.955.468.2112.6

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value372600350550515639566513
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

gmt:RrpfJointVentures


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312014-12-312013-12-312012-12-31
Value3622984208196323272417
Percentage of LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo97.349.7120.114.818.850.648.081.2

us-gaap:LongTermDebtPercentageBearingFixedInterestRate us-gaap:LongtermDebtType

us-gaap:LongTermDebtPercentageBearingFixedInterestRate

gmt:RecourseFixedRateDebtUnsecuredEight


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value0.960.00960.04350.0260.0250.0370.060.05750.05750.055
Percentage of LongTermDebtPercentageBearingFixedInterestRate100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

gmt:RecourseFixedRateDebtUnsecuredEighteenMember


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value4.00.05630.0120.0520.0450.03250.039
Percentage of LongTermDebtPercentageBearingFixedInterestRate416.7586.527.6200.0180.087.865.0

gmt:RecourseFixedRateDebtUnsecuredEleven


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value1.130.01070.03850.04850.04850.0250.0370.04850.04850.057
Percentage of LongTermDebtPercentageBearingFixedInterestRate117.7111.588.5186.5194.067.661.784.384.3103.6

gmt:RecourseFixedRateDebtUnsecuredFifteen


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value3.50.0470.0450.03250.03250.04850.04850.0390.0550.0425
Percentage of LongTermDebtPercentageBearingFixedInterestRate364.6489.6103.4125.0130.0131.180.867.895.777.3

gmt:RecourseFixedRateDebtUnsecuredFive


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