Railcar Leasing and Management Services Group - Selected consolidating income statement information for the Leasing Group (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021
Revenues:
Revenues		$ 416.8	$ 293.3	$ 889.5		$ 624.0
Operating profit (1):
Total operating profit		73.0	57.8	127.8		109.3
Select expense information:
Depreciation (3)				136.2		131.8
Selling, engineering, and administrative expenses		45.0	46.2	89.7		90.9
Profit recognized at sales-type lease commencement (1)		0.0	0.0	1.3	[1]	0.0
Loss on extinguishment of debt		1.5	11.7	1.5		11.7
Sustainable Railcar Conversions
Select expense information:
Depreciation (3)		3.9	2.6	6.1		2.6
Operating Segments [Member]
Revenues:
Revenues		416.8	293.3	889.5		624.0
Operating profit (1):
Total operating profit		119.2	84.3	199.8		153.8
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Revenues:
Revenues		195.3	185.1	378.4		368.6
Operating profit (1):
Total operating profit		$ 105.5	$ 81.1	$ 185.3		$ 159.4
Operating Income (Loss), Percent Change		30.10%		16.20%
Operating Profit Margin		54.00%	43.80%	49.00%		43.20%
Select expense information:
Depreciation (3)	[2],[3]	$ 59.4	$ 57.2	$ 116.6		$ 111.8
Depreciation, Depletion, and Amortization, Percent Change	[2],[3]	3.80%		4.30%
Maintenance and compliance	[3]	$ 27.3	25.3	$ 56.5		50.9
Maintenance Costs, Percent Change	[3]	7.90%		11.00%
Operating lease expense	[3]	$ 5.3	4.7	$ 10.3		9.3
Operating Leases, Rent Expense, Percent Change	[3]	12.80%		10.80%
Selling, engineering, and administrative expenses	[3]	$ 12.6	13.2	$ 25.4		24.5
Selling, Engineering, and Administrative Expense, Percent Change	[3]	(4.50%)		3.70%
Interest (4)	[4]	$ 46.0	57.0	$ 84.7		102.7
Interest Expense, Percent Change	[4]	(19.30%)		(17.50%)
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Leasing and Management [Member]
Revenues:
Revenues		$ 195.3	185.1	$ 378.4		368.6
Revenues, Percent Change		5.50%		2.70%
Operating profit (1):
Total operating profit		$ 78.6	$ 70.0	$ 146.6		$ 146.6
Operating Income (Loss), Percent Change		12.30%		0.00%
Operating Profit Margin		40.20%	37.80%	38.70%		39.80%
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Sales of Leased Railcars [Domain]
Operating profit (1):
Total operating profit		$ 26.9	$ 11.1	$ 38.7	[5]	$ 12.8
Operating Profit Margin		18.70%	15.50%	17.40%		14.40%

[1] Included in gains on dispositions of property – lease portfolio sales on our Consolidated Statements of Operations.

[2] Depreciation expense includes $3.9 million and $6.1 million for the three and six months ended June 30, 2022, respectively, related to the disposal of certain railcar components associated with our sustainable railcar conversion program. Additionally, for the three and six months ended June 30, 2021, depreciation expense includes $2.6 million related to our sustainable railcar conversion program.

[3] Operating profit includes: depreciation; fleet operating costs, which include maintenance, compliance, freight, and storage; rent and ad valorem taxes; and selling, engineering, and administrative expenses. Amortization of deferred profit on railcars sold from the Rail Products Group to the Leasing Group is included in the operating profit of the Leasing Group, resulting in the recognition of depreciation expense based on our original manufacturing cost of the railcars. Interest expense is not a component of operating profit and includes the effect of hedges.

[4] Interest expense for the three and six months ended June 30, 2022 includes $1.5 million of loss on extinguishment of debt associated with the repayment of TRIP Railcar Co.'s outstanding term loan agreement. Interest expense for the three and six months ended June 30, 2021 includes $11.7 million of loss on extinguishment of debt associated with the refinancing of our partially-owned subsidiaries' debt.

[5] Includes $1.3 million selling profit associated with sales-type leases for the six months ended June 30, 2022.