Operating Segments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Operating segments
Number of operating segments | segment			2
Revenue:
Lease rent revenue	$ 31,337	$ 29,181	$ 61,572	$ 57,457
Maintenance reserve revenue	11,881	15,514	43,843	31,333
Spare parts and equipment sales	19,383	3,673	31,979	6,305
Gain on sale of leased equipment	3,527	258	4,509	3,250
Other revenue	1,716	992	3,888	1,992
Total revenue	67,844	49,618	145,791	100,337
Expenses:
Depreciation and amortization expense	16,015	16,188	32,644	32,607
Cost of spare parts and equipment sales	13,730	2,787	23,130	4,719
Write-down of equipment	2,277	1,893	15,285	3,929
General and administrative	13,065	10,685	26,265	22,437
Technical expense	2,448	1,803	4,740	3,499
Net finance costs	11,312	10,534	22,178	20,542
Total expenses	58,847	43,890	124,242	87,733
Earnings from operations	8,997	5,728	21,549	12,604
Total assets	1,386,354		1,386,354		$ 1,337,887
Operating Segments [Member] | Leasing and Related Operations
Revenue:
Lease rent revenue	31,337	29,181	61,572	57,457
Maintenance reserve revenue	11,881	15,514	43,843	31,333
Spare parts and equipment sales	12,874	900	19,299	900
Gain on sale of leased equipment	3,527	258	4,509	3,250
Other revenue	1,649	972	3,774	1,905
Total revenue	61,268	46,825	132,997	94,845
Expenses:
Depreciation and amortization expense	15,929	16,103	32,470	32,440
Cost of spare parts and equipment sales	9,918	648	14,623	648
Write-down of equipment	1,351	1,893	13,442	3,929
General and administrative	12,207	9,958	24,620	20,938
Technical expense	2,448	1,803	4,740	3,499
Net finance costs	11,312	10,414	22,178	20,327
Total expenses	53,165	40,819	112,073	81,781
Earnings from operations	8,103	6,006	20,924	13,064
Total assets	1,359,406		1,359,406		1,307,460
Operating Segments [Member] | Spare Parts Sales
Revenue:
Spare parts and equipment sales	6,509	2,773	12,680	5,405
Other revenue	276	590	450	948
Total revenue	6,785	3,363	13,130	6,353
Expenses:
Depreciation and amortization expense	86	85	174	167
Cost of spare parts and equipment sales	3,812	2,139	8,507	4,071
Write-down of equipment	926		1,843
General and administrative	858	727	1,645	1,499
Net finance costs		120		215
Total expenses	5,682	3,071	12,169	5,952
Earnings from operations	1,103	292	961	401
Total assets	26,948		26,948		$ 30,427
Intersegment Eliminations [Member]
Revenue:
Other revenue	(209)	(570)	(336)	(861)
Total revenue	(209)	(570)	(336)	(861)
Expenses:
Earnings from operations	$ (209)	$ (570)	$ (336)	$ (861)