Derivative Instruments (Details 1) (Designated as hedging instrument, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense-increase/(decrease)
Expected effect during next twelve months	$ 5.1
Interest expense | Expired hedges | 2006 secured railcar equipment notes
Effect on interest expense-increase/(decrease)
Effect on interest expense	(0.3)		(0.3)	(0.4)
Expected effect during next twelve months	(0.3)	[1]
Interest expense | Expired hedges | Promissory notes
Effect on interest expense-increase/(decrease)
Effect on interest expense	3.1		3.3	3.5
Expected effect during next twelve months	2.9	[1]
Interest expense | Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense-increase/(decrease)
Effect on interest expense	6.1		6.0	17.4
Expected effect during next twelve months	5.1	[1]
Interest expense | Open hedges | Promissory notes
Effect on interest expense-increase/(decrease)
Effect on interest expense	15.8		18.4	19.6
Expected effect during next twelve months	15.7	[1]
Interest expense | Open hedges | TRIP Master Funding secured railcar equipment notes
Effect on interest expense-increase/(decrease)
Effect on interest expense	1.8		2.0	1.1
Expected effect during next twelve months	$ 1.5	[1]

[1] Based on the fair value of open hedges as of December 31, 2013