Basis of Presentation Basis of Presentation (non-printing) (Details) (USD $)	3 Months Ended			12 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Service Life [Member]	Dec. 31, 2014 Service Life [Member]	Mar. 31, 2014 Railcars [Member] Service Life [Member]	Mar. 31, 2014 Railcars [Member] Minimum [Member]	Mar. 31, 2014 Railcars [Member] Minimum [Member] Service Life [Member]	Mar. 31, 2014 Railcars [Member] Maximum [Member]	Mar. 31, 2014 Railcars [Member] Maximum [Member] Service Life [Member]
Change in Accounting Estimate [Line Items]
Change in accounting estimate			$ 3,500,000	$ 14,000,000.0
Property, Plant and Equipment, Useful Life						30 years	27 years	38 years	42 years
Average Increase (Decrease) in Estimated Railcar Useful Life					2 years 2 months 12 days
Depreciation, Nonproduction	62,100,000	60,900,000	0	21,900,000
Net Income (Loss) Attributable to Parent	$ 42,100,000	$ 27,100,000
Earnings Per Share, Diluted	$ 0.90	$ 0.57
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Diluted Earnings Per Share			$ 0.08	$ 0.30