INCOME TAXES - Reconciliation of Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ 925	$ 0	$ 0
State	(174)	30	76
Total current	751	30	76
Deferred
Federal	1,951	(1,744)	18,293
State	1,428	(301)	3,163
Total deferred	3,379	(2,045)	21,456
Tax benefit (expense)	$ 4,130	$ (2,015)	$ 21,532