Derivative Instruments (Details 1) - Designated as hedging instrument - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense - increase/(decrease)
Expected effect during next twelve months		$ 4.9		$ 4.9
Interest expense | Expired hedges | 2006 secured railcar equipment notes
Effect on interest expense - increase/(decrease)
Effect on interest expense		(0.1)	$ (0.1)	(0.2)	$ (0.2)
Expected effect during next twelve months	[1]	(0.3)		(0.3)
Interest expense | Expired hedges | Promissory notes
Effect on interest expense - increase/(decrease)
Effect on interest expense		0.5	0.7	1.2	1.5
Expected effect during next twelve months	[1]	0.0		0.0
Interest expense | Expired hedges | TRIP Holdings warehouse loan
Effect on interest expense - increase/(decrease)
Effect on interest expense		1.2	1.3	2.5	2.6
Expected effect during next twelve months	[1]	4.9		4.9
Interest expense | Open hedge | Promissory notes
Effect on interest expense - increase/(decrease)
Effect on interest expense		1.6	3.8	5.3	7.7
Expected effect during next twelve months	[1]	0.0		0.0
Interest expense | Open hedge | TRIP Master Funding secured railcar equipment notes
Effect on interest expense - increase/(decrease)
Effect on interest expense		0.4	$ 0.4	0.7	$ 0.8
Expected effect during next twelve months	[1]	$ 1.1		$ 1.1

[1] Based on the fair value of open hedges as of June 30, 2015