Debt - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Apr. 20, 2022
Corporate Segment [Member] \| Senior Notes [Member] \| 4.55% Senior Notes Due October 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.55%
Corporate Segment [Member] \| Revolving Credit Facility [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 450.0
Proceeds from Lines of Credit	70.0
Repayments of Lines of Credit	20.0
Line of Credit Facility, Remaining Borrowing Capacity	371.7
Line of Credit Facility, Maximum Borrowing Capacity	$ 192.1
Debt Instrument, Interest Rate, Effective Percentage	1.75%
Line of Credit Facility, Interest Rate at Period End	0.25%
Corporate Segment [Member] \| Letter of Credit [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount	$ 28.3
TILC [Member] \| Railcar Leasing and Management Services Group [Member] \| Revolving Credit Facility [Member] \| Line of Credit [Member] \| TILC Warehouse Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	2.09%
Debt Instrument, Face Amount	$ 1,000.0
Borrowings on Warehouse Loan Facility	57.2
Repayments on Warehouse Loan Facility	1.6
Line of Credit Facility, Remaining Borrowing Capacity Exclusive of Current Restrictions	$ 382.6
Wholly-owned subsidiaries \| Railcar Leasing and Management Services Group [Member] \| Secured Debt [Member] \| TRL-2022 Series 2022-1 Class A Green Secured Railcar Equipment Notes \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.55%
Debt Instrument, Face Amount		$ 244.8
Minimum \| Corporate Segment [Member] \| Revolving Credit Facility [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	0.30%
Line of Credit Facility, Interest Rate at Period End	0.175%
Maximum \| Corporate Segment [Member] \| Revolving Credit Facility [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	0.40%

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Line of Credit Facility, Remaining Borrowing Capacity Exclusive of Current Restrictions

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- Definition

Repayments on Warehouse Loan Facility

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- Definition

Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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The effective interest rate at the end of the reporting period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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