Note 5. Partially Owned Subsidiaries (Details)	3 Months Ended								12 Months Ended			42 Months Ended
	Dec. 31, 2024 USD ($) board_member	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2024 USD ($) subsidiary board_member	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($) board_member
Noncontrolling Interest [Line Items]
Gains on dispositions of property:	$ 22,900,000	$ 13,400,000	$ 24,200,000	$ 2,800,000	$ 36,400,000	$ 7,500,000	$ 30,400,000	$ 15,300,000	$ 63,300,000	$ 89,600,000	$ 152,700,000
Revenues	$ 629,400,000	$ 798,800,000	$ 841,400,000	$ 809,600,000	$ 797,900,000	$ 821,300,000	$ 722,400,000	$ 641,700,000	3,079,200,000	$ 2,983,300,000	$ 1,977,300,000
Signal Rail Holdings LLC
Noncontrolling Interest [Line Items]
Revenues									$ 1,400,000
Signal Rail Holdings LLC
Noncontrolling Interest [Line Items]
Equity Method Investment, JV Majority Ownership Percentage	87.60%								87.60%			87.60%
Equity Method Investment, Ownership Percentage	12.40%								12.40%			12.40%
Proceeds from Sales of Business, Affiliate and Productive Assets									$ 142,800,000			$ 741,400,000
Gains on dispositions of property:									18,800,000
Proceeds from Equity Method Investment, Distribution									2,000,000
Equity Method Investments	$ 21,200,000								21,200,000			21,200,000
Partially-Owned Subsidiaries [Member] | Partially-Owned Subsidiaries [Member]
Noncontrolling Interest [Line Items]
Carrying Value of Investment In Partially-Owned Consolidated Subsidiary	$ 133,000,000.0								$ 133,000,000.0			$ 133,000,000.0
Railcar Leasing and Services Group [Member] | Partially-Owned Subsidiaries [Member] | Partially-Owned Subsidiaries [Member]
Noncontrolling Interest [Line Items]
Number of Subsidiaries | subsidiary									2
Number of Board Members | board_member	7								7			7
Number of Board Members of Subsidiary, Designated by Parent | board_member	2								2			2
Parent Company Guarantees	$ 0								$ 0			$ 0
Railcar Leasing and Services Group [Member] | Partially-Owned Subsidiaries [Member] | TRIP Holdings
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	42.60%								42.60%			42.60%
Railcar Leasing and Services Group [Member] | Partially-Owned Subsidiaries [Member] | RIV 2013 Holdings
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	30.50%								30.50%			30.50%
Railcar Leasing and Services Group [Member] | Partially-Owned Subsidiaries [Member] | TRIP Holdings & RIV 2013
Noncontrolling Interest [Line Items]
Carrying Value of Investment In Partially-Owned Consolidated Subsidiary	$ 130,400,000								$ 130,400,000			$ 130,400,000
Rail Products Group [Member] | Partially-Owned Subsidiaries [Member]
Noncontrolling Interest [Line Items]
Carrying Value of Investment In Partially-Owned Consolidated Subsidiary	$ 2,600,000								$ 2,600,000			$ 2,600,000
Noncontrolling Interest, Ownership Percentage by Parent	51.00%								51.00%			51.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.00%								49.00%			49.00%