EQUITY-BASED COMPENSATION (Schedule of Equity-based Compensation Expense for Restricted Stock Awards and Non-Qualified Stock Options) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Equity-based compensation expense	$ 8,074	$ 6,757	$ 8,597
Income tax benefits	(2,826)	(2,365)	(3,009)
Total equity-based compensation expense, net of tax	5,248	4,392	5,588
Cost of revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Equity-based compensation expense	482	169	237
Selling and marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Equity-based compensation expense	1,340	837	1,630
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Equity-based compensation expense	557	538	718
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Equity-based compensation expense	$ 5,695	$ 5,213	$ 6,012