FAIR VALUE MEASUREMENTS (Details 2) (USD $)				12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011 Government-sponsored enterprise securities Investments due in less than 1 year	Dec. 31, 2011 Government-sponsored enterprise securities Investments due in 1 to 2 years	Dec. 31, 2011 Corporate notes	Dec. 31, 2012 Corporate notes Investments due in less than 1 year	Dec. 31, 2011 Corporate notes Investments due in less than 1 year	Dec. 31, 2011 Corporate notes Investments due in 1 to 2 years
Marketable securities with unrealized losses
Less Than 12 Months - Estimated Fair Value	$ 55,952,000	$ 5,021,000	$ 3,988,000		$ 27,045,000	$ 33,847,000	$ 13,096,000
Less Than 12 Months - Gross Unrealized Losses	(55,000)	(1,000)	(12,000)		(8,000)	(28,000)	(14,000)
Total - Estimated Fair Value	55,952,000	5,021,000	3,988,000		27,045,000	33,847,000	13,096,000
Total - Gross Unrealized Losses	(55,000)	(1,000)	(12,000)		(8,000)	(28,000)	(14,000)
Sale of marketable securities
Proceeds from the sale of marketable securities				809,000
Realized loss recognized from sale				$ 2,000