SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Investments
Fair value of investment	$ 5,330	$ 21,825
Accounts Receivable
Bad debt (recovery) expenses	(14)	(76)	(3,066)
Auction-rate securities
Investments
Fair value of investment	$ 2,251	$ 2,251
Minimum
Investments
Term of original or remaining maturity to classify available-for-sale securities as short-term (in days)	90
Minimum | Auction-rate securities
Investments
Short-term interest rate reset period (in days)	7
Period of contractual maturities (in years)	10
Maximum
Cash and Cash Equivalents
Term of original or remaining maturity to classify investments as cash and cash equivalents (in days)	90
Maximum | Auction-rate securities
Investments
Short-term interest rate reset period (in days)	28