Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 industry segment	Mar. 31, 2012	Dec. 31, 2012
Segment and Geographic Information
Number of reporting segments	2
Number of industries in which business activities are conducted	1
Industry Segment Information
Total revenues	$ 156,075	$ 138,332
Equipment trading expenses	15,611	12,563
Depreciation and amortization expense	49,317	45,205
Net (gain) on sale of leasing equipment	(10,261)	(10,760)
Interest and debt expense	28,883	26,625
Income before income taxes	54,741	47,998
Equipment held for sale	50,652	44,044	47,139
Goodwill at the end of the period	71,898	71,898	71,898
Total assets at the end of the period	3,802,107	3,164,877	3,701,194
Purchases of leasing equipment and investments in finance leases	195,221	123,100
Net (gain) on interest rate swaps	(3,152)	(2,972)
Intercompany expenses	72,451	63,709
[EquipmentLeasingMember]
Industry Segment Information
Total revenues	134,895	121,805
Depreciation and amortization expense	48,581	44,170
Net (gain) on sale of leasing equipment	(10,261)	(10,760)
Interest and debt expense	28,160	25,781
Income before income taxes	51,002	46,169
Equipment held for sale	19,634	16,812
Goodwill at the end of the period	70,898	70,898
Total assets at the end of the period	3,724,228	3,087,464
Purchases of leasing equipment and investments in finance leases	194,673	123,100
[EquipmentTradingMember]
Industry Segment Information
Total revenues	21,180	16,527
Equipment trading expenses	15,611	12,563
Depreciation and amortization expense	736	1,035
Interest and debt expense	723	844
Income before income taxes	3,739	1,829
Equipment held for sale	31,018	27,232
Goodwill at the end of the period	1,000	1,000
Total assets at the end of the period	77,879	77,413
Purchases of leasing equipment and investments in finance leases	548
[IntersegmentEliminationMember]
Industry Segment Information
Total revenues	0
Intercompany expenses	$ 0