ACQUISITION - Summary of Unaudited Proforma Financial Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Combinations [Abstract]
Revenues	$ 81,962	$ 81,792	$ 164,288	$ 165,999
Net loss	$ (13,900)	$ (19,462)	$ (29,134)	$ (28,108)
Net Income per share (in dollars per share)	$ (0.69)	$ (0.98)	$ (1.46)	$ (1.56)
Basic and diluted (in shares)	20,053	19,876	19,985	17,992