EARNINGS PER SHARE (EPS) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator [Abstract]
Net income per the Consolidated Statements of operations	$ 11,795	$ 11,164	$ 33,573	$ 34,582
Denominator [Abstract]
Weighted Average Number of Shares Outstanding utilized in the calculation of basic EPS (in shares)	34,408,801	33,831,618	34,212,431	33,666,202
Common stock equivalents resulting from the dilutive effect of in-the-money outstanding stock options (in shares)	89,016	49,705	75,348	117,206
Weighted average number of shares outstanding utilized in the calculation of diluted EPS (in shares)	34,497,817	33,881,323	34,287,779	33,783,408
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	1,330,792	2,746,738	1,323,076	1,245,159