Summary of Significant Accounting Policies (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2011
Summary of Significant Accounting Policies (Textual) [Abstract]
Authorization for repurchase shares by board of directors					$ 200
Shares repurchased, Shares	1,692,229	0	1,692,229	0
Cash Settlement for repurchase of stock shares			6.0
Net receivables in Energy Equipment Group			20.00%
Cost of Shares repurchased	41.2		41.2
Share repurchase program effective date					Jan. 01, 2011
Share repurchase program expiry date					Dec. 31, 2012
Maximum period to own lease fleet to adopt emerging industry policy						1 year
Minimum period to own lease fleet to recognize sale of Railcars as net gain loss						1 year
Decrease in revenue from reclassification adjustments of prior period		$ 2.2		$ 12.2