ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Effect of Topic 606 on Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Consolidated Statement of Operations
Net revenues	$ 262,946	$ 257,966	$ 763,907	$ 755,033
Other operating costs	30,999	33,184	92,631	97,734
Income from operations	15,924	9,540	36,876	16,463
Income (loss) before income taxes	6,809	(5,741)	(9,169)	(27,286)
Net income (loss)	4,369	(4,161)	(5,321)	(20,258)
Comprehensive income (loss)	6,133	$ (4,178)	(3,799)	$ (20,309)
Before adoption of ASC 606 | ASU 2014-09
Condensed Consolidated Statement of Operations
Net revenues	263,591		766,773
Other operating costs	31,735		95,568
Income from operations	15,833		36,805
Income (loss) before income taxes	6,718		(9,240)
Net income (loss)	4,278		(5,392)
Comprehensive income (loss)	6,042		(3,870)
Adjustments | ASU 2014-09
Condensed Consolidated Statement of Operations
Net revenues	645		2,866
Other operating costs	736		2,937
Income from operations	(91)		(71)
Income (loss) before income taxes	(91)		(71)
Net income (loss)	(91)		(71)
Comprehensive income (loss)	$ (91)		$ (71)