EARNINGS PER SHARE - EPS Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
EARNINGS PER SHARE
Net loss from continuing operations applicable to common shareholders	$ (84,413)	$ (4,161)	$ 1,637	$ (17,734)	$ (81,113)	$ (7,856)	$ (900)	$ (17,537)	$ (16,097)	$ (18,437)	$ (20,258)	$ (26,293)	$ (104,671)	$ (107,406)	$ (319,117)
Income (loss) from discontinued operations, net of income taxes					(15)	378	572			572		950		935	(7,974)
Net loss	$ (84,413)	$ (4,161)	$ 1,637	$ (17,734)	$ (81,128)	$ (7,478)	$ (328)	$ (17,537)	$ (16,097)	$ (17,865)	$ (20,258)	$ (25,343)	$ (104,671)	$ (106,471)	$ (327,091)
Shares of common stock outstanding used to compute basic per common share amounts	36,410	36,340	36,287	36,085	36,032	36,008	35,949	35,742	36,187	35,846	36,239	35,900	36,270,920	35,933,222	35,635,448
Shares used to compute diluted per common share amounts	36,410	36,340	36,544	36,085					36,187		36,239		36,270,920	35,933,222	35,635,448
Basic and Diluted:
Loss from continuing operations per share applicable to common stock (in dollars per share)					$ (2.25)	$ (0.22)	$ (0.03)	$ (0.49)		$ (0.51)		$ (0.73)	$ (2.89)	$ (2.99)	$ (8.96)
Income (loss) from discontinued operations, net of income taxes (in dollars per share)						0.01	0.02			0.01		0.02		0.03	(0.22)
Basic and diluted loss per common share (in dollars per share)					$ (2.25)	$ (0.21)	$ (0.01)	$ (0.49)		$ (0.50)		$ (0.71)	$ (2.89)	$ (2.96)	$ (9.18)