SELECTED QUARTERLY INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 276,542	$ 216,703	$ 205,592	$ 212,546	$ 256,357	$ 203,263	$ 196,779	$ 235,182	$ 911,383	$ 891,581	$ 888,467
Gross profit	198,935	135,805	128,512	138,109	178,446	128,840	122,962	159,568	601,361	589,816	608,794
(Loss) from operations	(1,745)	(46,767)	(52,338)	(34,028)	15,453	(17,258)	(23,163)	7,936	(134,878)	(17,032)	93,177
Net (loss) income	$ 918	$ (30,338)	$ (32,296)	$ (28,717)	$ 16,413	$ (7,587)	$ (10,409)	$ 12,200	$ (90,433)	$ 10,617	$ 98,548
(Loss) earnings per share
Basic (dollars per share)	$ 0.01	$ (0.38)	$ (0.41)	$ (0.37)	$ 0.21	$ (0.10)	$ (0.13)	$ 0.16	$ (1.14)	$ 0.14	$ 1.27
Diluted (dollars per share)	$ 0.01	$ (0.38)	$ (0.41)	$ (0.37)	$ 0.20	$ (0.10)	$ (0.13)	$ 0.15	$ (1.14)	$ 0.13	$ 1.19