STOCK-BASED COMPENSATION (Details) (USD $)	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 2004 Employee stock purchase plan	Jun. 30, 2013 RSUs Performance-contingent Senior management Employee	Jun. 30, 2012 RSUs Performance-contingent Senior management Employee	Jun. 30, 2013 RSUs Performance-contingent Senior management Employee	Jun. 30, 2012 RSUs Performance-contingent Senior management Employee	Jun. 30, 2013 2012 Employee Incentive Plan	Jun. 30, 2013 2013 Restricted Stock Awards Plan RSAs Performance-contingent Senior management Employee Item	Jun. 30, 2013 2012 Restricted Stock Awards Plan RSAs Performance-contingent Senior management Employee Item	Jun. 30, 2013 2012 Restricted Stock Awards Plan RSAs Performance-contingent Senior management Employee Item	Dec. 31, 2012 2012 Restricted Stock Awards Plan RSAs Performance-contingent Senior management Employee Item
Information related to stock-based compensation
Stock-based compensation expense	$ 7,162,000	$ 5,979,000	$ 13,257,000	$ 12,214,000		$ 32,000	$ 80,000	$ 72,000	$ 177,000		$ 217,000	$ 59,000	$ 146,000
Shares remaining available for issuance					343,233					3,514,872
Number of performance conditions which need to be achieved											1	1	1
Number of possible performance conditions											3	3	3
Number of performance goals deemed achieved											1			1