Note 6. Railcar Leasing and Services Group - Income Statement Information (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues		$ 629.4	$ 798.8	$ 841.4	$ 809.6	$ 797.9	$ 821.3	$ 722.4	$ 641.7	$ 3,079.2	$ 2,983.3	$ 1,977.3
Cost of revenues:		474.4	629.3	662.4	644.9	637.0	679.5	601.2	538.5	2,411.0	2,456.2	1,609.6
Selling, engineering, and administrative expenses:		61.6	60.5	61.3	52.3	48.6	49.1	54.3	49.9	235.7	201.9	185.4
Lease portfolio sales										57.3	82.8	127.5
Gain (Loss) on Disposition of Other Assets										6.0	6.8	25.2
Total operating profit		$ 112.0	$ 122.4	$ 141.9	$ 115.2	$ 148.7	$ 100.2	$ 99.1	$ 69.0	491.5	417.0	334.0
Depreciation and amortization										293.8	293.2	276.4
Profit recognized at sales-type lease commencement (1)	[1]									0.0	0.0	1.3
Railcar Leasing and Services Group [Member] | Railroad Transportation Equipment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other fleet operating costs	[2],[3]									$ 32.3	$ 31.5	46.6
Other fleet operating costs, Percent Change	[2],[3]									2.50%	(32.40%)
Interest Expense	[2],[4]									$ 234.4	$ 227.2	186.7
Interest Expense, Percent Change	[2],[4]									3.20%	21.70%
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues										$ 3,574.3	$ 3,520.4	2,737.0
Total operating profit										653.4	550.1	467.4
Operating Segments [Member] | Railcar Leasing and Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues										$ 1,143.2	$ 1,041.0	851.5
Revenues, Percent Change										9.80%	22.30%
Cost of revenues:	[5]									$ 665.2	$ 630.3	527.9
Cost of revenues, Percent Change	[5]									5.50%	19.40%
Selling, engineering, and administrative expenses:	[6]									$ 77.0	$ 62.0	59.1
Selling, Engineering, and Administrative Expense, Percent Change										24.20%	4.90%
Lease portfolio sales	[6]									$ 57.3	$ 82.8	127.5	[7]
Gain (Loss) on Disposition of Other Assets										5.7	6.0	9.8
Total operating profit										$ 464.0	$ 437.5	$ 401.8
Operating Income (Loss), Percent Change										6.10%	8.90%
Operating Profit Margin										40.60%	42.00%	47.20%
Operating Profit Margin, excluding Lease portfolio sales										35.60%	34.10%	32.20%
Depreciation and amortization										$ 262.2	$ 258.0	$ 249.3
Operating Segments [Member] | Railcar Leasing and Services Group [Member] | Railroad Transportation Equipment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	[2],[6],[8]									$ 240.1	$ 238.5	234.4
Depreciation, Depletion, and Amortization, Percent Change	[2],[8]									0.70%	1.70%
Cost, Maintenance	[2],[6],[9]									$ 131.8	$ 130.5	112.1
Maintenance Costs, Percent Change	[2],[9]									1.00%	16.40%
Operating Segments [Member] | Railcar Leasing and Services Group [Member] | Sustainable Railcar Conversions
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization											$ 5.6	12.1
Leasing and management [Member] | Operating Segments [Member] | Railcar Leasing and Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues										$ 867.8	$ 813.8	756.4
Revenues, Percent Change										6.60%	7.60%
Maintenance services [Domain] | Operating Segments [Member] | Railcar Leasing and Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues	[10]									$ 234.0	$ 170.1	80.9
Revenues, Percent Change	[10]									37.60%	110.30%
Digital & Logistics Services | Operating Segments [Member] | Railcar Leasing and Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues										$ 41.4	$ 57.1	$ 14.2
Revenues, Percent Change										(27.50%)	302.10%

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

[2] Includes wholly-owned railcars, partially-owned railcars, and railcars under leased-in arrangements.

[3] Other fleet operating costs include freight, storage, rent, and ad valorem taxes.

[4] Interest expense is not a component of operating profit and includes the effect of hedges.

[5] Includes depreciation and amortization expense, maintenance and compliance expense, and other fleet operating costs related to our lease fleet, as well as operating costs for our maintenance services and digital and logistics services businesses.

[6] Significant expense categories and amounts align with the segment-level information that is regularly provided to and reviewed by the CODM. Intersegment expenses are included within the amounts shown.

[7] Includes $1.3 million selling profit associated with sales-type leases for the year ended December 31, 2022.

[8] Depreciation and amortization expense includes $5.6 million and $12.1 million for the years ended December 31, 2023 and 2022, respectively, related to the disposal of certain railcar components associated with our sustainable railcar conversion program. There were no disposals under this program during the year ended December 31, 2024. Additionally, depreciation and amortization expense includes deferred profit related to new railcar additions, sustainable railcar conversions, railcar modifications, and other betterments, resulting in the recognition of depreciation expense based on the original cost of the railcars and services.

[9] Maintenance and compliance expense is reported at cost with respect to the services performed by our maintenance services business to support the railcars in our lease fleet.

[10] Revenues related to services performed by the maintenance services business on Company-owned railcars under full-service lease agreements are eliminated within the Railcar Leasing and Services Group and are excluded from the totals reported on this line.