Basis of Presentation Basis of Presentation (non-printing) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Service Life [Member]	Sep. 30, 2014 Service Life [Member]	Dec. 31, 2014 Railcars [Member] Service Life [Member]	Dec. 31, 2014 Railcars [Member] Minimum [Member]	Dec. 31, 2014 Railcars [Member] Minimum [Member] Service Life [Member]	Dec. 31, 2014 Railcars [Member] Maximum [Member]	Dec. 31, 2014 Railcars [Member] Maximum [Member] Service Life [Member]	Dec. 31, 2014 Scenario, Forecast [Member] Service Life [Member]
Change in Accounting Estimate [Line Items]
Change in accounting estimate					$ 3.5	$ 10.5						$ 14.0
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
Depreciation expense			211.9	196.1	5.5	16.5						21.9
Net Income (Loss) Attributable to Parent	$ 51.3	$ 53.8	$ 146.5	$ 116.0
Earnings Per Share, Diluted	$ 1.14	$ 1.15	$ 3.18	$ 2.45
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Diluted Earnings Per Share					$ 0.08	$ 0.23						$ 0.30