Railcar Leasing and Management Services Group - Narrative (Details) - Railcar Leasing and Management Services Group [Member] $ in Millions	Mar. 31, 2021 USD ($)
Minimum
Segment Reporting Information [Line Items]
Lessor, Operating Lease, Term of Contract	1 year
Maximum
Segment Reporting Information [Line Items]
Lessor, Operating Lease, Term of Contract	10 years
Wholly-owned subsidiaries
Segment Reporting Information [Line Items]
Net book value of unpledged equipment	$ 1,078.8
Wholly-owned subsidiaries | Secured Debt [Member]
Segment Reporting Information [Line Items]
Debt Instrument, Collateral Amount	4,740.3
TRIP Holdings [Member] | Secured Debt [Member] | TRIP Master Funding Secured Railcar Equipment Notes [Member]
Segment Reporting Information [Line Items]
Debt Instrument, Collateral Amount	1,139.8
Trinity Rail Leasing 2012 [Member] | Secured Debt [Member] | TRL 2012 Secured Railcar Equipment Notes - RIV 2013 [Member]
Segment Reporting Information [Line Items]
Debt Instrument, Collateral Amount	$ 472.1