INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, if recognized, would affect the effective tax rate	$ 600
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at Beginning of Year	2,554	$ 2,554
Additions for tax positions of prior years	594	0
Balance at End of Year	3,148	2,554	$ 2,554
Accrued interest and penalties	900	400
Interest and penalties	$ 500	$ 100	$ 200