NET INCOME (LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income (loss)	$ 85,071	$ (3,465)	$ 44,869
Denominator:
Denominator for basic net income (loss) per share — weighted-average outstanding shares	32,167	31,950	30,215
Effect of dilutive securities:
Stock options and restricted stock (in shares)	269	0	426
Denominator for diluted net income (loss) per share — weighted-average outstanding shares	32,436	31,950	30,641
Net income (loss) per share — basic (in dollars per share)	$ 2.64	$ (0.11)	$ 1.48
Net income (loss) per share — diluted (in dollars per share)	$ 2.62	$ (0.11)	$ 1.46
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	60	56	24
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	194		80
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	59	55	23
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1	1	1