Derivative Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Effect on interest expense - increase/(decrease)
Interest expense	$ 45.8		$ 47.8	$ 141.5		$ 143.6
Designated as hedging instrument | Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense - increase/(decrease)
Expected effect during next twelve months	5.2			5.2
Reclassification out of Accumulated Other Comprehensive Income | Designated as hedging instrument | Expired hedges | 2006 secured railcar equipment notes
Effect on interest expense - increase/(decrease)
Interest expense	0		(0.1)	(0.2)		(0.3)
Expected effect during next twelve months	(0.3)	[1]		(0.3)	[1]
Reclassification out of Accumulated Other Comprehensive Income | Designated as hedging instrument | Expired hedges | Promissory notes
Effect on interest expense - increase/(decrease)
Interest expense	0.8		0.8	2.4		2.5
Expected effect during next twelve months	3.0	[1]		3.0	[1]
Reclassification out of Accumulated Other Comprehensive Income | Designated as hedging instrument | Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense - increase/(decrease)
Interest expense	1.3		1.5	4.8		4.5
Expected effect during next twelve months	5.2	[1]		5.2	[1]
Reclassification out of Accumulated Other Comprehensive Income | Designated as hedging instrument | Open hedges | Promissory notes
Effect on interest expense - increase/(decrease)
Interest expense	4.0		4.3	12.0		12.7
Expected effect during next twelve months	16.0	[1]		16.0	[1]
Reclassification out of Accumulated Other Comprehensive Income | Designated as hedging instrument | Open hedges | TRIP Master Funding secured railcar equipment notes
Effect on interest expense - increase/(decrease)
Interest expense	0.4		0.5	1.3		1.5
Expected effect during next twelve months	$ 1.5	[1]		$ 1.5	[1]

[1] Based on the fair value of open hedges as of September 30, 2013