Reportable Segments (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Reportable Segments
Number of reportable segments | segment				2
Number of operating segments | segment				2
Revenue:
Lease rent revenue		$ 46,984	$ 33,474	$ 129,710	$ 95,045
Revenue		19,370	20,370	56,855	64,212
Revenue From Sale Of Spare Parts		8,354	9,294	21,701	41,273
Gain on sale of leased equipment		1,256	174	2,142	4,684
Other revenue		2,010	2,549	5,762	6,439
Total revenue		77,974	65,861	216,170	211,653
Expenses:
Depreciation and amortization expense		19,861	16,142	55,600	48,786
Cost of spare parts and equipment sales		5,848	7,148	16,537	32,121
Write-down of equipment		1,215	6,226	4,793	19,668
General and administrative		18,124	14,308	50,517	40,574
Technical expense		2,290	2,605	9,199	7,345
Interest Expense		17,885	14,220	46,617	36,398
Total expenses		65,223	60,649	183,263	184,892
Earnings from operations		12,751	5,212	32,907	26,761
Total assets	[1]	1,965,196		1,965,196		$ 1,603,431
Operating Segments | Leasing and Related Operations
Revenue:
Lease rent revenue		46,984	33,474	129,710	95,045
Revenue		19,370	20,370	56,855	64,212
Revenue From Sale Of Spare Parts					19,300
Gain on sale of leased equipment		1,150	22	1,917	4,463
Other revenue		2,010	2,538	5,716	6,314
Total revenue		69,514	56,404	194,198	189,334
Expenses:
Depreciation and amortization expense		19,771	16,056	55,336	48,526
Cost of spare parts and equipment sales					14,623
Write-down of equipment		1,215	6,226	4,793	19,668
General and administrative		17,003	13,387	47,181	38,008
Technical expense		2,290	2,605	9,199	7,345
Interest Expense		17,885	14,220	46,617	36,398
Total expenses		58,164	52,494	163,126	164,568
Earnings from operations		11,350	3,910	31,072	24,766
Total assets		1,919,003		1,919,003		1,556,406
Operating Segments | Spare Parts Sales
Revenue:
Revenue From Sale Of Spare Parts		8,354	9,294	21,701	21,973
Gain on sale of leased equipment		106	152	225	221
Other revenue		274	247	1,596	697
Total revenue		8,734	9,693	23,522	22,891
Expenses:
Depreciation and amortization expense		90	86	264	260
Cost of spare parts and equipment sales		5,848	7,148	16,537	17,498
General and administrative		1,121	921	3,336	2,566
Total expenses		7,059	8,155	20,137	20,324
Earnings from operations		1,675	1,538	3,385	2,567
Total assets		46,193		46,193		$ 47,025
Eliminations
Revenue:
Other revenue		(274)	(236)	(1,550)	(572)
Total revenue		(274)	(236)	(1,550)	(572)
Expenses:
Earnings from operations		$ (274)	(236)	$ (1,550)	(572)
Reclassification
Expenses:
Write-down of equipment			700		2,600
Increase to cost of spare parts and equipment sales			700		2,600
Decrease to Write-down of equipment			$ (700)		$ (2,600)

[1] Total assets at September 30, 2018 and December 31, 2017, respectively, include the following assets of variable interest entities (“VIEs”) that can only be used to settle the liabilities of the VIEs: Cash $393 and $130; Restricted cash $155,420 and $40,272; Equipment $1,054,258 and $657,333; and Other assets $834 and $20,090, respectively.