Accounting Policies and Recent Accounting Pronouncements (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Property, Plant and Equipment [Line Items]
Reduction in depreciation expense due to change in residual values and estimated useful lives	$ 2,100,000	$ 5,800,000
Increase in pre tax income due to change in residual values and estimated useful lives	2,100,000	5,800,000
Increase in net income	1,900,000	5,000,000
Increase in diluted earnings per share (in dollars per share)	$ 0.10	$ 0.25
20-ft. standard dry van container [Member] | Current [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,050	1,050
Depreciable life		13 years
20-ft. standard dry van container [Member] | Prior [Member]
Property, Plant and Equipment [Line Items]
Residual Value	950	950
Depreciable life		12 years 6 months
40-ft. standard dry van container [Member] | Current [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,300	1,300
Depreciable life		13 years
40-ft. standard dry van container [Member] | Prior [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,150	1,150
Depreciable life		12 years 6 months
40-ft. high cube dry van container [Member] | Current [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,650	1,650
Depreciable life		13 years
40-ft. high cube dry van container [Member] | Prior [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,300	1,300
Depreciable life		12 years 6 months
20-ft. refrigerated container [Member] | Current [Member]
Property, Plant and Equipment [Line Items]
Residual Value	2,750	2,750
Depreciable life		12 years
20-ft. refrigerated container [Member] | Prior [Member]
Property, Plant and Equipment [Line Items]
Residual Value	2,250	2,250
Depreciable life		12 years
40-ft. high cube refrigerated container [Member] | Current [Member]
Property, Plant and Equipment [Line Items]
Residual Value	3,500	3,500
Depreciable life		12 years
40-ft. high cube refrigerated container [Member] | Prior [Member]
Property, Plant and Equipment [Line Items]
Residual Value	3,000	3,000
Depreciable life		12 years
Other specialized containers [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Residual Value	1,000	1,000
Depreciable life		12 years 6 months
Other specialized containers [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Residual Value	$ 3,500	$ 3,500
Depreciable life		15 years
Railcar Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciable life		40 years
Railcar Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciable life		43 years