Segment and Geographic Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 12, 2016 USD ($)
Segment Reporting Information [Line Items]
Operating and Capital Leases Income Statement Lease Revenue	$ 313,856	$ 302,120	$ 281,939	$ 265,602	$ 259,547	$ 247,789	$ 158,333	$ 163,025	$ 1,163,517	$ 828,694	$ 707,839
Number of Reportable Segments | segment									2
Gross Profit	1,095	1,369	1,328	392	386	232	0	0	$ 4,184	618	0
Equipment trading expenses									33,235	15,800	0
Net (gain) loss on sale of leasing equipment	(10,749)	$ (10,263)	$ (9,639)	$ (5,161)	4,261	$ 12,319	$ 1,930	$ 1,837	(35,812)	20,347	(2,013)
Depreciation and amortization expense									500,720	392,592	300,470
Interest and debt expense									282,347	184,014	140,644
Realized loss on derivative instruments, net									900	3,438	5,496
Income before income taxes									265,828	(10,097)	135,127
Equipment held for sale	43,195				99,863				43,195	99,863	0
Goodwill at the end of the period	236,665				236,665				236,665	236,665	0	$ 236,665
Total assets at the end of the period	9,577,625				8,713,571				9,577,625	8,713,571	4,658,997
Purchases of leasing equipment and investments in finance leases									1,562,863	629,332	398,799
Unrealized (gain) loss on derivative instruments, net									(1,397)	(4,405)	2,240
Write-off of debt costs									6,973	141	1,170
Costs and Expenses									657,075	632,686	428,374
Equipment leasing
Segment Reporting Information [Line Items]
Operating and Capital Leases Income Statement Lease Revenue									1,160,196	827,111	707,839
Gross Profit									0	0
Net (gain) loss on sale of leasing equipment									(35,812)	20,347	(2,013)
Depreciation and amortization expense									500,099	392,250	300,470
Interest and debt expense									280,909	183,377	140,644
Realized loss on derivative instruments, net									900	3,438	5,496
Income before income taxes									262,574	(6,302)	135,127
Equipment held for sale	31,534				81,804				31,534	81,804	0
Goodwill at the end of the period	220,864				220,864				220,864	220,864	0
Total assets at the end of the period	9,534,330				8,660,786				9,534,330	8,660,786	4,658,997
Purchases of leasing equipment and investments in finance leases									1,562,863	629,176	398,799
Equipment trading
Segment Reporting Information [Line Items]
Operating and Capital Leases Income Statement Lease Revenue									3,321	1,583	0
Gross Profit									4,184	618
Net (gain) loss on sale of leasing equipment									0	0	0
Depreciation and amortization expense									621	342	0
Interest and debt expense									1,438	637	0
Realized loss on derivative instruments, net									0	0	0
Income before income taxes									3,254	(3,795)	0
Equipment held for sale	11,661				18,059				11,661	18,059	0
Goodwill at the end of the period	15,801				15,801				15,801	15,801	0
Total assets at the end of the period	$ 43,295				$ 52,785				43,295	52,785	0
Purchases of leasing equipment and investments in finance leases									0	156	0
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues									0	0	0
Costs and Expenses									0	0	0
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Unrealized (gain) loss on derivative instruments, net									$ (1,397)	$ (4,405)	$ 2,240