Supplemental Cash Flow and Noncash Investing Transactions (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Vessel
Supplemental Cash Flow and Noncash Investing and Financing Transactions (Textual) [Abstract]
Aggregate fair value of liquidating distributions	$ 88.8	[1]
Number of vessels containing liquidating distributions	6

[1] In connection with the dissolutions of GATX's Clipper Fourth Limited and Clipper Fourth APS affiliates, GATX received liquidating distributions of six vessels with an aggregate fair value of $88.8 million. See Note 6 for additional information.