Segment and Geographic Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Industry Segment Information
Number of operating segments | segment			2
Number of reportable segments | segment			2
Total leasing revenues	$ 321,397,000	$ 338,566,000	$ 642,865,000	$ 679,425,000
Trading margin	2,020,000	4,496,000	3,953,000	8,083,000
Net gain on sale of leasing equipment	4,537,000	7,519,000	8,614,000	15,988,000
Depreciation and amortization expense	133,292,000	135,348,000	265,987,000	269,957,000
Interest and debt expense	66,874,000	82,260,000	135,876,000	165,780,000
Realized (gain) loss on derivative instruments, net	11,000	(669,000)	(224,000)	(1,373,000)
Income before income taxes	77,276,000	95,963,000	160,186,000	197,610,000
Payments to Acquire Productive Assets	157,382,000	106,005,000	219,788,000	149,986,000
Equipment held for sale	144,956,000		144,956,000		$ 114,504,000
Goodwill at the end of the period	236,665,000		236,665,000		236,665,000
Total assets at the end of the period	9,681,754,000		9,681,754,000		9,642,633,000
Equipment trading revenues	16,903,000	23,209,000	32,283,000	41,037,000
Expenses	183,757,000	173,954,000	363,204,000	343,410,000
Unrealized (gain) loss on derivative instruments, net	300,000	1,300,000	286,000	2,253,000
Debt termination expense	0	558,000	31,000	558,000
Equipment Leasing
Industry Segment Information
Total leasing revenues	319,620,000	337,897,000	640,657,000	677,967,000
Trading margin	0	0	0	0
Net gain on sale of leasing equipment	4,537,000		8,614,000
Depreciation and amortization expense	133,116,000	135,181,000	265,634,000	269,603,000
Interest and debt expense	66,483,000	81,883,000	135,182,000	165,057,000
Realized (gain) loss on derivative instruments, net	11,000	(667,000)	(223,000)	(1,369,000)
Income before income taxes	74,843,000	92,294,000	156,360,000	190,760,000
Payments to Acquire Productive Assets	157,382,000	106,005,000	219,788,000	149,986,000
Equipment held for sale	106,035,000		106,035,000		89,755,000
Goodwill at the end of the period	220,864,000		220,864,000		220,864,000
Total assets at the end of the period	9,563,689,000		9,563,689,000		9,596,263,000
Equipment Trading
Industry Segment Information
Total leasing revenues	1,777,000	669,000	2,208,000	1,458,000
Trading margin	2,020,000	4,496,000	3,953,000	8,083,000
Net gain on sale of leasing equipment	0	0	0	0
Depreciation and amortization expense	176,000	167,000	353,000	354,000
Interest and debt expense	391,000	377,000	694,000	723,000
Realized (gain) loss on derivative instruments, net	0	(2,000)	(1,000)	(4,000)
Income before income taxes	2,433,000	3,669,000	3,826,000	6,850,000
Payments to Acquire Productive Assets	0	$ 0	0	0
Equipment held for sale	38,921,000		38,921,000		24,749,000
Goodwill at the end of the period	15,801,000		15,801,000		15,801,000
Total assets at the end of the period	$ 118,065,000		118,065,000		$ 46,370,000
Intersegment Eliminations
Industry Segment Information
Equipment trading revenues			0	0
Expenses			$ 0	$ 0