INCOME TAXES - Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (200)	$ 12	$ 60
State	115	24	150
Foreign	1,960	1,378	982
Total current	1,875	1,414	1,192
Deferred:
Federal	49,570	(301)	(7,069)
State	(4,833)	(1,007)	4,962
Foreign	(816)	338	155
Change in valuation allowance	(64,236)	2,072	2,767
Total deferred	(20,315)	1,102	815
Total	$ (18,440)	$ 2,516	$ 2,007