NET INCOME PER SHARE - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic net income (loss) per share:
Net income (loss) from continuing operations	$ 20,144	$ (31,881)	$ 46,316	$ (8,129)
Net loss from discontinued operations	0	0	0	(10,370)
Net income (loss)	$ 20,144	$ (31,881)	$ 46,316	$ (18,499)
Weighted average common shares outstanding, basic (in shares)	37,267	35,279	37,143	33,682
Basic net income per common share from continuing operations (in dollars per share)	$ 0.54	$ (0.90)	$ 1.25	$ (0.24)
Basic net loss per common share from discontinued operations (in dollars per share)	0.00	0.00	0.00	(0.31)
Net income per share - basic (in dollars per share)	$ 0.54	$ (0.90)	$ 1.25	$ (0.55)
Diluted net income (loss) per share:
Net income (loss) from continuing operations	$ 20,144	$ (31,881)	$ 46,316	$ (8,129)
Net loss from discontinued operations	0	0	0	(10,370)
Net income (loss)	$ 20,144	$ (31,881)	$ 46,316	$ (18,499)
Weighted average common shares outstanding, basic (in shares)	37,267	35,279	37,143	33,682
Effect of dilutive securities:
2016 Convertible notes (in shares)	2,594	0	1,615	0
Stock options and restricted stock (in shares)	655	0	644	0
Weighted average common shares for diluted earnings per share (in shares)	40,516	35,279	39,402	33,682
Diluted net income (loss) per common share from continuing operations (in dollars per share)	$ 0.50	$ (0.90)	$ 1.18	$ (0.24)
Diluted net loss per common share from discontinued operations (in dollars per share)	0.00	0.00	0.00	(0.31)
Net income per share - diluted (in dollars per share)	$ 0.50	$ (0.90)	$ 1.18	$ (0.55)