GOODWILL AND INTANGIBLE ASSETS - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of goodwill	$ 251,900	$ 0	$ 0	$ 251,850
Depreciation and amortization expense		$ 11,800	$ 6,200	$ 5,100