Derivative Instruments (Details 1) (Designated as hedging instrument, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Expired hedges | 2006 secured railcar equipment notes
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	$ (0.3)		$ (0.4)		$ (0.4)
Expected effect during next twelve months	(0.3)	[1]
Expired hedges | Promissory notes
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	3.3		3.5		3.8
Expected effect during next twelve months	3.1	[1]
Expired hedges | TRIP Holdings
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	6.0		17.4		29.3
Expected effect during next twelve months	5.6	[1]
Open hedges | Promissory notes
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	18.4	[2]	19.6	[2]	19.7	[2]
Expected effect during next twelve months	16.7	[1],[2]
Open hedges | TILC Warehouse
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	0	[2]	0	[2]	0.5	[2]
Expected effect during next twelve months	0	[1],[2]
Open hedges | TRIP Master Funding secured railcar equipment notes
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	2.0	[2]	1.1	[2]	0	[2]
Expected effect during next twelve months	$ 1.8	[1],[2]

[1] )Based on fair value as of December 31, 2012

[2] Cash flows related to open hedges are included as a change in accrued liabilities in the Consolidated Statements of Cash Flows.