Railcar Leasing and Management Services Group - Schedule of proceeds from leased railcars (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales		$ 56.7	$ 71.1
Operating profit on lease portfolio sales (1)		69.0	54.8
Operating Segments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)		110.8	80.6
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)	[1]	$ 85.5	$ 79.8
Operating Profit Margin		42.00%	43.60%
Operating Segments [Member] | Sales of Leased Railcars [Domain] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales		$ 56.7	$ 71.1
Operating profit on lease portfolio sales (1)	[1]	$ 13.5	$ 11.8	[2]
Operating Profit Margin		23.80%	14.80%
Operating Segments [Member] | Sales of Leased Railcars, Excluding Sales-Type Leases | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)		$ 13.5	$ 10.5	[3]

[1] 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.

[2] Includes $1.3 million selling profit associated with sales-type leases for the three months ended March 31, 2022.

[3] Excludes $1.3 million selling profit associated with sales-type leases for the three months ended March 31, 2022.