v3.19.3.a.u2
Fair Value Disclosure (Details)
$ in Millions |
12 Months Ended |
|
USD ($)
Instrument
|
USD ($)
Instrument
|
USD ($)
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Property, Plant and Equipment, Net |
$ 6,707.2
|
$ 6,532.7
|
|
|
Derivative Liability |
13.6
|
30.6
|
|
|
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months |
1.3
|
|
|
|
Asset Impairment Charges |
6.6
|
9.0
|
$ 8.6
|
|
Fair Value, Recurring [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
13.6
|
30.6
|
|
|
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
13.6
|
30.6
|
|
|
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
0.0
|
0.0
|
|
|
Cardinal Marine [Domain] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Noncontrolling Interest, Ownership Percentage by Parent |
|
|
|
50.00%
|
Portfolio Management [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Asset Impairment Charges |
6.2
|
4.5
|
3.7
|
|
Changes Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Asset Impairment Charges |
0.0
|
|
0.0
|
|
Reported Value Measurement [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Property, Plant and Equipment, Net |
1.6
|
10.9
|
|
|
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
7.6
|
|
|
|
Interest Rate Contract [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
0.6
|
7.7
|
|
|
Interest Rate Contract [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
0.6
|
7.7
|
|
|
Interest Rate Contract [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
0.0
|
0.0
|
|
|
Interest Rate Contract [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
$ 450.0
|
$ 500.0
|
|
|
Derivative, Number of Instruments Held | Instrument |
(8)
|
(9)
|
|
|
Interest Rate Contract [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Derivative Liability |
$ 336.5
|
$ 501.9
|
|
|
Derivative, Number of Instruments Held | Instrument |
(7)
|
(8)
|
|
|
Interest Rate Contract [Member] | Other Nonoperating Income (Expense) [Member] | Cash Flow Hedging [Member] |
|
|
|
|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
|
|
Effective portion reclassified from accumulated other comprehensive loss |
|
$ 0.0
|
$ 0.0
|
|
X |
- DefinitionAmount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.
+ References
+ Details
Name: |
us-gaap_AssetImpairmentCharges |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:monetaryItemType |
Balance Type: |
debit |
Period Type: |
duration |
|
X |
- DefinitionThe estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.
+ References
+ Details
Name: |
us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:monetaryItemType |
Balance Type: |
credit |
Period Type: |
duration |
|
X |
- DefinitionThe effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.
+ References
+ Details
Name: |
us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:monetaryItemType |
Balance Type: |
credit |
Period Type: |
duration |
|
X |
- DefinitionFair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.
+ References
+ Details
Name: |
us-gaap_DerivativeLiabilities |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:monetaryItemType |
Balance Type: |
credit |
Period Type: |
instant |
|
X |
- DefinitionThe number of derivative instruments of a particular group held by the entity.
+ References
+ Details
Name: |
us-gaap_DerivativeNumberOfInstrumentsHeld |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:integerItemType |
Balance Type: |
na |
Period Type: |
instant |
|
X |
- DefinitionLine items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
+ Details
Name: |
us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:stringItemType |
Balance Type: |
na |
Period Type: |
duration |
|
X |
- DefinitionThe parent entity's interest in net assets of the subsidiary, expressed as a percentage.
+ References
+ Details
Name: |
us-gaap_MinorityInterestOwnershipPercentageByParent |
Namespace Prefix: |
us-gaap_ |
Data Type: |
num:percentItemType |
Balance Type: |
na |
Period Type: |
instant |
|
X |
- DefinitionAmount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.
+ References
+ Details
Name: |
us-gaap_PropertyPlantAndEquipmentNet |
Namespace Prefix: |
us-gaap_ |
Data Type: |
xbrli:monetaryItemType |
Balance Type: |
debit |
Period Type: |
instant |
|
X |
- Details
Name: |
us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gmt_CardinalMarineDomain |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_StatementBusinessSegmentsAxis=gmt_PortfolioManagementMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_FairValueByMeasurementBasisAxis=us-gaap_ChangeDuringPeriodFairValueDisclosureMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_InvestmentTypeAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
X |
- Details
Name: |
us-gaap_IncomeStatementLocationAxis=us-gaap_OtherNonoperatingIncomeExpenseMember |
Namespace Prefix: |
|
Data Type: |
na |
Balance Type: |
|
Period Type: |
|
|
|