Investments (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Jun. 03, 2014
Investments
Capital contribution to joint ventures				$ (4,610)	$ (630)
Investment in WMES joint ventures at beginning of the period				41,295
Capital contribution				4,610	630
Earnings from joint venture				243
Deferred gain on engine sale				(1,212)
Distribution				(1,167)
Foreign currency translation adjustment		$ 967		526
Investment in WMES joint ventures at end of the period		44,295		44,295
Management fees		$ 500	$ 400	$ 1,100	$ 800
WMES
Investments
Ownership interest (as a percent)		100.00%	50.00%	100.00%	50.00%
Capital contribution to joint ventures				$ (4,610)
Investment in WMES joint ventures at beginning of the period				27,272
Capital contribution				4,610
Earnings from joint venture				367
Deferred gain on engine sale				(1,212)
Distribution				(1,167)
Investment in WMES joint ventures at end of the period		$ 29,870		29,870
Gain on sale of equipemnt				$ 1,200
Amortized Gain Period				15 years
Amortized Gain Residual Value Percent				55.00%
Consolidated Statements of Income
Revenue		7,752	$ 6,532	$ 16,998	$ 12,930
Expenses		7,209	6,023	16,390	11,750
WMES net income		543	$ 509	608	$ 1,180
Consolidated Balance Sheets
Total assets		307,152		307,152		$ 256,126
Total liabilities		238,790		238,790		195,258
Total WMES net equity		68,362		68,362		$ 60,868
CASC
Investments
Ownership interest (as a percent)							50.00%
Capital contribution to joint ventures	$ 15,000
Investment in WMES joint ventures at beginning of the period				14,023
Capital contribution	$ (15,000)
Earnings from joint venture				(124)
Foreign currency translation adjustment				526
Investment in WMES joint ventures at end of the period		$ 14,425		$ 14,425