Partially-Owned Subsidiaries - Narrative (Details) $ in Millions	6 Months Ended
Jun. 30, 2025 USD ($) board_member subsidiary
Signal Rail Holdings LLC
Noncontrolling Interest [Line Items]
Equity Method Investment, JV Majority Ownership Percentage	87.40%
Equity Method Investment, Ownership Percentage	12.60%
Equity Method Investments	$ 20.7
Partially-owned subsidiaries
Noncontrolling Interest [Line Items]
Parent Company Guarantees	$ 0.0
Leasing & Services \| Partially-owned subsidiaries
Noncontrolling Interest [Line Items]
Number of Subsidiaries \| subsidiary	2
Number of Board Members \| board_member	7
Number of Board Members of Subsidiary, Designated by Parent \| board_member	2
Partially-owned subsidiaries \| Rail Products Group [Member]
Noncontrolling Interest [Line Items]
Carrying Value of Investment In Partially-Owned Consolidated Subsidiary	$ 2.7
Noncontrolling Interest, Ownership Percentage by Parent	51.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.00%
TRIP Holdings & RIV 2013 \| Leasing & Services
Noncontrolling Interest [Line Items]
Carrying Value of Investment In Partially-Owned Consolidated Subsidiary	$ 130.9
TRIP Holdings [Member] \| Leasing & Services
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	42.60%
RIV 2013 Holdings \| Leasing & Services
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	30.50%

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