INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Increase (decrease) in valuation allowance	$ (11,100)	$ (6,500)	$ (600)
Valuation allowance for deferred tax assets	62,865	$ 51,846	$ 58,300
Decrease in unrecognized tax benefits is reasonably possible	$ 2,000