NET INCOME PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic (loss) income per share
Net (loss) income	$ (11,785)	$ 6,454	$ (45,070)	$ 37,139
Denominator (in shares)	60,320,369	58,567,603	59,960,507	58,076,865
Basic net (loss) income per share (in dollars per share)	$ (0.20)	$ 0.11	$ (0.75)	$ 0.64
Numerator:
Net (loss) income	$ (11,785)	$ 6,454	$ (45,070)	$ 37,139
Add interest expense on convertible debt, net of tax				803
Net income (loss), diluted	$ (11,785)	$ 6,454	$ (45,070)	$ 37,942
Denominator:
Denominator (in shares)	60,320,369	58,567,603	59,960,507	58,076,865
Add effect of dilutive securities:
Stock options and equivalents		2,296,000		2,382,000
Convertible debt				1,379,000
Denominator for diluted net (loss) income per share (in shares)	60,320,369	60,864,107	59,960,507	61,838,173
Diluted net (loss) income per share (in dollars per share)	$ (0.20)	$ 0.11	$ (0.75)	$ 0.61
Total number of antidilutive shares excluded from the diluted net income (loss) per share	21,807	6,026	21,450	1,451
Convertible notes due 2021
Add effect of dilutive securities:
Total number of antidilutive shares excluded from the diluted net income (loss) per share	17,931	4,093	17,931
Stock options and equivalents
Add effect of dilutive securities:
Total number of antidilutive shares excluded from the diluted net income (loss) per share	3,876	1,933	3,519	1,451