Consolidation of Variable Interest Entities as a Non-Controlling Interest (Details) (USD $)	3 Months Ended			3 Months Ended		12 Months Ended
	Mar. 31, 2013 Fund	Mar. 31, 2012	Dec. 31, 2012	Mar. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member]	Mar. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2010 Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Number of specific Japanese funds	2
Net proceeds from sale of equipment portfolios	$ 0	$ 10,320,000			$ 10,300,000
Gain on sale of equipment portfolios	0	1,256,000			1,300,000
Containers transferred to specific Japanese funds						16,000,000
Cash				15,300,000
Fair value of net investment in direct finance leases	85,980,000		85,554,000	4,200,000
Non-controlling interest				19,500,000
Gain or loss recognized upon the initial consolidation				0
Net income attributable to non-controlling interest	0	65,000		100,000
Sale and leaseback transaction of containers				85,000,000
Net book value of containers transferred	1,786,000		1,847,000	79,400,000
Cash held by investor funds				6,400,000
Collateralized financing obligations	$ 970,949,000		$ 888,990,000	$ 95,100,000