SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Selected Quarterly Financial Information [Abstract]
Revenue	$ 240,123	$ 224,542	$ 232,462	$ 238,462	$ 243,745	$ 247,224	$ 246,897	$ 244,357	$ 935,589	$ 982,223	$ 922,654
Gross profit	74,650	62,585	64,164	64,232	65,909	65,233	64,818	64,955	265,631	260,915	250,753
Loss from continuing operations, before income taxes	(3,776)	(10,669)	(8,160)	(9,747)	(15,980)	(28,791)	(264,822)	(15,367)	(32,352)	(324,960)	(138,727)
(Loss) income from discontinued operations, net of income taxes	(7,273)	(174)	75	233	(1,451)	7,457	94	(2,379)	(7,139)	3,721	2,452
Net loss	$ (12,471)	$ (11,264)	$ (8,234)	$ (9,537)	$ (18,443)	$ (16,783)	$ (244,807)	$ (19,674)	$ (41,506)	$ (299,707)	$ (147,468)
Loss from continuing operations, basic and diluted (in USD per share)	$ (0.06)	$ (0.12)	$ (0.14)	$ (0.17)	$ (0.27)	$ (0.38)	$ (3.62)	$ (0.28)	$ (0.46)	$ (4.56)	$ (2.19)
Income (loss) from discontinued operations, basic and diluted (in USD per share)	(0.06)	0.00	0.00	0.00	(0.02)	0.11	0.00	(0.03)	(0.08)	0.05	0.04
Net loss, basic and diluted (in USD per share)	$ (0.12)	$ (0.12)	$ (0.14)	$ (0.17)	$ (0.29)	$ (0.27)	$ (3.62)	$ (0.31)	$ (0.54)	$ (4.51)	$ (2.15)