EARNINGS PER SHARE (EPS) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator [Abstract]
Net income per the Consolidated Statements of operations	$ 11,531	$ 12,338	$ 21,778	$ 23,418
Denominator [Abstract]
Weighted Average Number of Shares Outstanding utilized in the calculation of basic EPS (in shares)	34,180,983	33,695,418	34,113,168	33,582,080
Common stock equivalents resulting from the dilutive effect of in-the-money outstanding stock options (in shares)	48,219	170,490	66,928	211,636
Weighted average number of shares outstanding utilized in the calculation of diluted EPS (in shares)	34,229,202	33,865,908	34,180,096	33,793,716
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	2,203,024	1,263,877	1,331,331	1,232,350