Debt (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt (Textual) [Abstract]
Operating assets pledged as collateral for notes	$ 639.5
Expiry of registration statement	August 2013
Amount of secured debt available to be borrowed in accordance with public debt covenants	863.3
Minimum debt covenant fixed charge coverage ratio	1.2
Fixed charge coverage ratio	1.7
Line of Credit US [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	560.0
Maturity date of revolving credit facility	May 2015
Availability under credit facility	550.2
Letter of credit issued	9.8
Annual commitment fees	0.9	0.4	0.4
Line of Credit Europe [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	58.3
Availability under credit facility	29.7
Maximum amount of GRE transfer to GATX relating to loans and dividends	26.9
Restricted net assets	$ 385.1
Restricted net assets of equity	less 50% of free cash flow