FAIR VALUE OF CERTAIN FINANCIAL ASSETS AND LIABILITIES (Details 4) (USD $)	12 Months Ended									12 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Auction rate securities	Dec. 31, 2010 Auction rate securities	Dec. 31, 2009 Auction rate securities	Dec. 31, 2008 Auction rate securities	Dec. 31, 2011 2011 ARS Agreement	Jun. 30, 2011 2011 ARS Agreement	Dec. 31, 2011 2010 ARS Agreement	Dec. 31, 2010 2010 ARS Agreement	Mar. 31, 2010 2010 ARS Agreement	Dec. 31, 2011 Put options related to auction rate securities	Dec. 31, 2010 Put options related to auction rate securities	Oct. 01, 2013 2011 Put Option	Jul. 01, 2013 2011 Put Option	Dec. 31, 2011 2010 Put Option	Mar. 22, 2011 2010 Put Option
ARS Agreement
Amount of securities of par value									$ 24,500,000			$ 54,200,000			$ 1,000,000	$ 1,000,000		$ 13,600,000
Redemption of investment securities through the exercise of the put option																	27,100,000
Redemption of investment securities at par through normal market channels								3,700,000		4,000,000	7,400,000
Fair market value of investments													3,000,000
Current portion of fair market value of the put option included in prepaid expenses and other current assets	20,912,000	17,022,000											900,000
Long term portion of fair market value of the put option included in other assets													2,100,000
Corresponding gain (loss) to put option recorded in other income													(700,000)	3,800,000
Face value of investments				44,800,000
Amortized cost basis	434,476,000	291,246,000		35,900,000
Fair value of available-for-sale securities				3,300,000
Impairment of investments available-for-sale				5,000,000
Trading auction rate securities, in short-term and long-term investments				32,500,000
Impairment of investments, trading securities				4,000,000
Net loss recognized through earnings on trading securities
(Loss) on transfer from available-for-sale to trading				(2,438,000)	(4,876,000)
Gain on trading securities sold				2,604,000	375,000
(Loss) gain on trading securities held				(210,000)	572,000
Loss on trading securities				(44,000)	(3,929,000)
Other-than-temporary impairment that was previously deemed credit loss related, charged through earnings					600,000	3,900,000	500,000
Resulted gain or loss on revaluation of investment securities included in other income	$ (800,000)	$ (800,000)	$ (3,900,000)