Reportable Segments (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) segment	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Reportable Segments
Number of operating segments | segment				2
Revenue:
Lease rent revenue		$ 43,081	$ 31,337	$ 82,726	$ 61,572
Maintenance reserve revenue		22,045	11,881	37,485	43,843
Revenue From Sale Of Spare Parts		7,061	19,383	13,347	31,979
Gain on sale of leased equipment		245	3,527	886	4,509
Other Income		1,871	1,716	3,752	3,888
Total revenue		74,303	67,844	138,196	145,791
Expenses:
Depreciation and amortization expense		18,384	16,015	35,739	32,644
Cost of spare parts and equipment sales		5,906	14,656	10,689	24,973
Write-down of equipment		3,578	1,351	3,578	13,442
Cost of spare parts sales				32,393
General and administrative		16,782	13,065	32,393	26,265
Technical expense		3,232	2,448	6,909	4,740
Interest Expense		15,138	11,312	28,732	22,178
Total expenses		63,020	58,847	118,040	124,242
Earnings from operations		11,283	8,997	20,156	21,549
Total assets	[1]	1,783,435		1,783,435		$ 1,603,431
Reclassification
Expenses:
Write-down of equipment			900		1,800
Increase to Cost of spare parts and equipment sales				1,800
Decrease to Write-down of equipment				(1,800)
Operating Segments | Leasing and Related Operations
Revenue:
Lease rent revenue		43,081	31,337	82,726	61,572
Maintenance reserve revenue		22,045	11,881	37,485	43,843
Revenue From Sale Of Spare Parts			12,874		19,299
Gain on sale of leased equipment		187	3,484	767	4,440
Other Income		1,856	1,649	3,706	3,774
Total revenue		67,169	61,225	124,684	132,928
Expenses:
Depreciation and amortization expense		18,297	15,929	35,565	32,470
Cost of spare parts and equipment sales			9,918		14,623
Write-down of equipment		3,578	1,351	3,578	13,442
Cost of spare parts sales				30,178
General and administrative		15,683	12,207		24,620
Technical expense		3,232	2,448	6,909	4,740
Interest Expense		15,138	11,312	28,732	22,178
Total expenses		55,928	53,165	104,962	112,073
Earnings from operations		11,241	8,060	19,722	20,855
Total assets		1,737,537		1,737,537		1,556,406
Operating Segments | Spare Parts Sales
Revenue:
Revenue From Sale Of Spare Parts		7,061	6,509	13,347	12,680
Gain on sale of leased equipment		58	43	119	69
Other Income		210	276	1,323	450
Total revenue		7,329	6,828	14,789	13,199
Expenses:
Depreciation and amortization expense		87	86	174	174
Cost of spare parts and equipment sales		5,906	4,738	10,689	10,350
Cost of spare parts sales				2,215
General and administrative		1,099	858		1,645
Total expenses		7,092	5,682	13,078	12,169
Earnings from operations		237	1,146	1,711	1,030
Total assets		45,898		45,898		$ 47,025
Eliminations
Revenue:
Other Income		(195)	(209)	(1,277)	(336)
Total revenue		(195)	(209)	(1,277)	(336)
Expenses:
Earnings from operations		$ (195)	$ (209)	$ (1,277)	$ (336)

[1] Total assets at June 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 $553 and $130; Restricted cash $37,880 and $40,272; Equipment $652,648 and $657,333; and Other $1,207 and $20,090, respectively.