Derivative Instruments (Details Textual) (USD $) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Jul. 31, 2011 Interest Rate Swap, TRIP Master Funding secured railcar equipment notes	Sep. 30, 2012 Designated as Hedging Instrument Expired hedges 2006 secured railcar equipment notes		Sep. 30, 2012 Designated as Hedging Instrument Expired hedges Promissory notes		Sep. 30, 2012 Designated as Hedging Instrument Expired hedges TRIP Holdings
Derivative Instruments (Textual) [Abstract]
Changes in fair value of cash flow hedges which is being amortized to income			$ 4.5		$ 24.5
Expected effect during next twelve months			(0.3)	[1]	3.2	[1]	5.9	[1]
Interest rate swap, notional amount		94.1	200.0		370.0		788.5
Remaining AOCL balance of foreign exchange hedges with quarterly maturities	$ 0

[1] Based on fair value as of September 30, 2012