Investments (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Jun. 03, 2014	May 25, 2011
Investments
Investment in WMES joint ventures at beginning of the period				$ 45,406
Investment					$ 5,545
Earnings from joint venture				6,055
Distribution				(1,880)
Foreign Currency Translation Adjustment				620
Investment in WMES joint ventures at end of the period		$ 49,262		49,262
Deferred gain on engine sale				(939)
Property Subject to or Available for Operating Lease, Net						$ 1,199,883	$ 1,136,603
Equity Method Investments		49,262		45,406		$ 49,262	45,406
Sale of engines				53,849	61,825
Gain (Loss) on Sale of Leased Equipment
Investments
Gain on sale of equipment				900
WMES
Investments
Ownership interest (as a percent)						100.00%			50.00%
Investment in WMES joint ventures at beginning of the period				32,470
Earnings from joint venture				5,055
Distribution				(1,880)
Investment in WMES joint ventures at end of the period		35,202		35,202
Deferred gain on engine sale				(443)
Equity Method Investments		35,202		$ 32,470		$ 35,202	32,470
Sale of engines					46,100
Amortized Gain Period				15 years
Amortized Gain Residual Value Percent				55.00%
Consolidated Statements of Income
Revenue		12,286	$ 8,549	$ 32,146	25,547
Expenses		6,366	7,496	20,820	23,886
WMES net income		5,920	$ 1,053	11,326	1,661
Consolidated Balance Sheets
Total assets						241,904	293,299
Total liabilities						162,369	219,881
Total WMES net equity						79,535	73,418
WMES | Other Revenue
Investments
Management fees				1,800	500
WMES | Gain (Loss) on Sale of Leased Equipment
Investments
Gain on sale of equipment					$ 1,200
CASC
Investments
Ownership interest (as a percent)								50.00%
Investment in WMES joint ventures at beginning of the period				12,936
Investment	$ 15,000
Earnings from joint venture				1,000
Foreign Currency Translation Adjustment				620
Investment in WMES joint ventures at end of the period		14,060		14,060
Deferred gain on engine sale				(496)
Equity Method Investments		$ 14,060		$ 12,936		$ 14,060	$ 12,936