Debt (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) Instrument	Dec. 31, 2015 USD ($) Instrument	Dec. 31, 2014 USD ($)
Line of Credit Facility [Line Items]
Non-Recourse Debt	$ 0.0	$ 6.9
Operating assets pledged as collateral for notes	301.1
Other Short-term Borrowings	3.8	7.4
Annual commitment fees	$ 1.5	1.0	$ 1.0
Fixed charge coverage ratio	3.3
Minimum debt covenant fixed charge coverage ratio	1.2
Amount of secured debt available to be borrowed in accordance with public debt covenants	$ 1,363.9
Line of Credit US [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	600.0	$ 575.0
Rail Facility [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	250.0
Line of Credit Europe [Member]
Line of Credit Facility [Line Items]
Maximum amount of GRE transfer to GATX relating to loans and dividends	157.4
Restricted net assets	$ 359.9
Fair Value Hedging [Member]
Line of Credit Facility [Line Items]
Derivative, Number of Instruments Held | Instrument	8	8
Rail Facility [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	$ 250.0