Supplemental Cash Flow and Noncash Investing Transactions (Details Textual) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 USD ($) Car	Dec. 31, 2013 USD ($) Car	Dec. 31, 2012 USD ($)	Dec. 31, 2013 Singco/Somagas [Member] USD ($)	Dec. 31, 2014 Aae Cargo Ag [Member] USD ($)	Dec. 31, 2013 Aae Cargo Ag [Member] USD ($)	Dec. 31, 2012 Aae Cargo Ag [Member] USD ($)	Dec. 31, 2014 Aae Cargo Ag [Member] USD ($)	Dec. 31, 2014 Aae Cargo Ag [Member] EUR (€)	Dec. 31, 2013 Aae Cargo Ag [Member] USD ($)	Dec. 31, 2013 Aae Cargo Ag [Member] EUR (€)
Noncash or Part Noncash Divestitures [Line Items]
Portfolio proceeds	$ 264.0	$ 385.3	$ 288.9		$ 0	$ 91.1	$ 0	$ 77.0	€ 68.2	$ 91.1	€ 67.5
Supplemental Cash Flow and Noncash Investing and Financing Transactions (Textual) [Abstract]
Aggregate fair value of liquidating distributions	$ 1.1	$ 22.9	$ 0	$ 151.8
Number of railcars received	62	640