SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, NET INCOME (LOSS) PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator: [Abstract]
Net income	$ 11,052	$ 6,779	$ 16,935	$ 5,201
Denominator: [Abstract]
Denominator for basic net income per share - weighted-average outstanding shares (in shares)	27,758	27,243	27,607	26,279
Effect of dilutive securities: [Abstract]
Stock options and restricted stock	591	430	530	412
Denominator for diluted net income per share - weighted-average outstanding shares (in shares)	28,349	27,673	28,137	26,691
Net income per share - basic (in dollars per share)	$ 0.40	$ 0.25	$ 0.61	$ 0.20
Net income per share - diluted (in dollars per share)	$ 0.39	$ 0.24	$ 0.60	$ 0.19
Antidilutive securities excluded from computation of earnings per share	0	0	0	0