UNAUDITED QUARTERLY FINANCIAL INFORMATION - Summary of Quarterly Results (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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	$ 470,351	$ 499,076	$ 533,997	$ 564,764	$ 547,861	$ 580,185	$ 617,944	$ 607,533	$ 2,068,188	$ 2,353,523	$ 2,480,962
Gross profit	154,919	162,628	193,744	203,091	172,434	184,702	207,735	206,874	714,382	771,745	824,422
Operating income (loss)	13,889	26,654	48,718	35,482	(2,881)	19,961	48,884	46,389	124,743	112,353	(256,816)
Net (loss) income	$ (33,490)	$ (2,418)	$ 16,058	$ (15,262)	$ 58,839	$ (8,590)	$ 13,341	$ 6,190	$ (35,112)	$ 69,780	$ (150,262)
Weighted average shares outstanding:
Basic (in shares)	83,878	83,823	83,663	83,510	83,476	83,412	83,332	83,232	83,720	83,364	68,789
Diluted (in shares)	83,878	83,823	140,942	83,510	94,388	83,412	83,409	83,368	83,720	86,171	68,789
(Loss) earnings per share:
Basic (in USD per share)	$ (0.46)	$ (0.09)	$ 0.13	$ (0.23)	$ 0.69	$ (0.10)	$ 0.16	$ 0.07	$ (0.64)	$ 0.83	$ (2.18)
Diluted (in USD per share)	$ (0.46)	$ (0.09)	$ 0.11	$ (0.23)	$ 0.62	$ (0.10)	$ 0.16	$ 0.07	$ (0.64)	$ 0.81	$ (2.18)