INCOME TAXES - Tax Provision/Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Federal:
Current	$ (376)	$ 0	$ (1,092)
Deferred	3,634	(29,082)	(22,177)
Federal income tax expense (benefit)	3,258	(29,082)	(23,269)
State:
Current	74	0	(350)
Deferred	(204)	1,110	(1,769)
State income tax expense (benefit)	(130)	1,110	(2,119)
Income tax expense (benefit)	$ 3,128	$ (27,972)	$ (25,388)