SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES-Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Taxes
Total revenue earned		$ 1,016		$ 2,240
Taxable income	$ (31,182)	(27,097)	$ (61,295)	(191,886)
Income tax expense		417		766
Vessel Management Services
Income Taxes
Total revenue earned	0	1,016	0	2,240
Taxable income		829		1,619
Income tax expense	$ 0	417	$ 0	766
Vessel Management Services | Intersegment Elimination
Income Taxes
Total revenue earned		$ 0		$ 0