Note 8. Debt Remaining Debt Principal Payments (Details) $ in Millions	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 234.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	717.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	260.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	767.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	838.7
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	2,243.7
Long-term Debt, Gross	5,062.7
Corporate Segment [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	50.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	400.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	0.0
Long-term Debt, Gross	450.0
Secured Debt [Member] | 2009 Secured Railcar Equipment Notes [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	14.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	14.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	11.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	14.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	19.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	67.6
Long-term Debt, Gross	142.3
Secured Debt [Member] | 2010 Secured Railcar Equipment Notes [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	22.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	20.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	22.3
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	18.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	20.6
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	131.0
Long-term Debt, Gross	235.9
Secured Debt [Member] | 2018 Secured Railcar Equipment Notes [Domain] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	17.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	19.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	19.1
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	19.1
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	14.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	344.9
Long-term Debt, Gross	434.9
Secured Debt [Member] | 2019 Secured Railcar Equipment Notes [Domain] [Domain] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	37.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	36.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	34.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	36.6
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	35.2
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	679.5
Long-term Debt, Gross	860.8
Secured Debt [Member] | 2020 Secured Railcar Equipment Notes [Domain] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	20.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	18.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	18.3
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	14.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	11.3
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	286.6
Long-term Debt, Gross	369.1
Secured Debt [Member] | TRL 2012 Secured Railcar Equipment Notes - RIV 2013 [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	19.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	19.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	22.7
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	28.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	31.3
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	230.3
Long-term Debt, Gross	352.5
Secured Debt [Member] | TRIP Master Funding Secured Railcar Equipment Notes [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	40.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	41.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	37.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	191.6
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	70.3
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	503.8
Long-term Debt, Gross	885.0
Promissory Notes [Member] | 2017 Secured Railcar Equipment Notes [Member] [Domain] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	44.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	44.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	44.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	44.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	635.2
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	0.0
Long-term Debt, Gross	812.8
Line of Credit [Member] | TILC Warehouse Facility [Member] | Railcar Leasing and Management Services Group [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	16.7
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	2.8
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	0.0
Long-term Debt, Gross	19.5
Line of Credit [Member] | TILC Warehouse Facility Termination Payments [Member] | Railcar Leasing and Management Services Group [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	499.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	0.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	0.0
Long-term Debt, Gross	$ 499.9