Debt (Details) - USD ($) $ in Millions	Sep. 30, 2016		Dec. 31, 2015
Debt Instrument [Line Items]
Unamortized discount	$ 31.5	[1]	$ 44.2
Less: unamortized debt issuance costs	(4.0)		(4.8)
Recourse, net of unamortized discount of $31.5 and $44.2	847.4	[1]	836.7
Non-recourse debt	2,287.4		2,390.7
Less: unamortized debt issuance costs	(27.7)		(32.0)
Non-recourse debt	2,259.7		2,358.7
Total debt	3,107.1	[1]	3,195.4
Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	880.7	[1]	928.7
Partially-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	1,379.0	[1]	1,430.0
Corporate
Debt Instrument [Line Items]
Corporate - Recourse	818.2		805.7
Less: unamortized debt issuance costs	(3.9)		(4.7)
Long-term debt, net of debt issuance costs	814.3		801.0
Railcar Leasing and Management Services Group
Debt Instrument [Line Items]
Capital lease obligations, net of unamortized debt issuances costs of $0.1 and $0.1	33.1		35.7
Non-recourse debt	2,259.7		2,358.7
Railcar Leasing and Management Services Group | Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	893.0		943.8
Less: unamortized debt issuance costs	(12.3)		(15.1)
Non-recourse debt	880.7		928.7
Railcar Leasing and Management Services Group | Partially-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	1,394.4		1,446.9
Less: unamortized debt issuance costs	(15.4)		(16.9)
Non-recourse debt	1,379.0		1,430.0
Line of credit | Revolving credit facility | Corporate
Debt Instrument [Line Items]
Corporate - Recourse	0.0		0.0
Line of credit | Revolving credit facility | Railcar Leasing and Management Services Group | TILC warehouse facility | Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	236.8		264.3
Senior notes, net of unamortized discount of $0.4 and $0.4 | Corporate
Debt Instrument [Line Items]
Corporate - Recourse	399.6		399.6
Unamortized discount	0.4		0.4
Convertible subordinated notes, net of unamortized discount | Corporate
Debt Instrument [Line Items]
Unamortized discount	31.1		43.8
Convertible subordinated notes, net of unamortized discount | Corporate | 3 7/8% Convertible Subordinated Notes Due 2036 [Member]
Debt Instrument [Line Items]
Corporate - Recourse	418.3		405.6
Other | Corporate
Debt Instrument [Line Items]
Corporate - Recourse	0.3		0.5
Capital lease obligations, net of unamortized debt issuances costs of $0.1 and $0.1 | Railcar Leasing and Management Services Group
Debt Instrument [Line Items]
Less: unamortized debt issuance costs	(0.1)		(0.1)
Non-recourse debt | Railcar Leasing and Management Services Group | 2006 secured railcar equipment notes | Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	198.0		204.1
Non-recourse debt | Railcar Leasing and Management Services Group | 2009 secured railcar equipment notes | Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	174.1		179.2
Non-recourse debt | Railcar Leasing and Management Services Group | 2010 secured railcar equipment notes | Wholly-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	284.1		296.2
Non-recourse debt | Railcar Leasing and Management Services Group | TRL 2012 secured railcar equipment notes (RIV 2013) | Partially-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	431.1		449.1
Non-recourse debt | Railcar Leasing and Management Services Group | TRIP Master Funding secured railcar equipment notes (TRIP Holdings) | Partially-owned subsidiaries
Debt Instrument [Line Items]
Non-recourse debt	$ 963.3		$ 997.8

[1] (unaudited)