INCOME TAXES - Unrecognized Tax Benefit Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gross unrecognized tax benefits, roll forward
Balance at the beginning of the period	$ 471	$ 935	$ 935
Decreases for tax positions related to the prior years	(462)	(464)	0
Balance at the end of the period	9	$ 471	$ 935
Accrued interest and penalties related to unrecognized tax benefits	$ 100