FAIR VALUE MEASUREMENTS AND FINANCIAL INSTRUMENTS (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Assets:
Marketable securities:	$ 26,340,000	$ 20,604,000
Long-term marketable equity securities
Gross Unrealized Gains	17,406,000	6,996,000
Gross Unrealized Losses	0	0
Equity securities
Long-term marketable equity securities
Cost basis	8,800,000	42,100,000
Gross Unrealized Gains	3,600,000
Gross Unrealized Losses		10,800,000
Fair value on a recurring basis | Quoted Market Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total Assets	385,030,000	583,511,000
Fair value on a recurring basis | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets:
Cash equivalents:	347,345,000	545,290,000
Fair value on a recurring basis | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Assets:
Marketable securities:	25,325,000	6,977,000
Long-term investments:	12,360,000	31,244,000
Fair value on a recurring basis | Significant Other Observable Inputs (Level 2)
Assets:
Total Assets	175,351,000	25,621,000
Fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | Commercial paper
Assets:
Cash equivalents:	81,890,000
Fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | Time deposits
Assets:
Cash equivalents:	92,446,000	11,994,000
Fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | Corporate debt securities
Assets:
Marketable securities:	1,015,000	13,627,000
Fair value on a recurring basis | Significant Unobservable Inputs (Level 3)
Assets:
Total Assets	9,300,000	8,100,000
Liabilities:
Contingent consideration arrangement	(48,931,000)
Fair value on a recurring basis | Significant Unobservable Inputs (Level 3) | Auction rate security
Assets:
Long-term investments:	9,300,000	8,100,000
Fair value on a recurring basis | Fair Value
Assets:
Total Assets	569,681,000	617,232,000
Liabilities:
Contingent consideration arrangement	(48,931,000)
Fair value on a recurring basis | Fair Value | Money market funds
Assets:
Cash equivalents:	347,345,000	545,290,000
Fair value on a recurring basis | Fair Value | Commercial paper
Assets:
Cash equivalents:	81,890,000
Fair value on a recurring basis | Fair Value | Time deposits
Assets:
Cash equivalents:	92,446,000	11,994,000
Fair value on a recurring basis | Fair Value | Corporate debt securities
Assets:
Marketable securities:	1,015,000	13,627,000
Fair value on a recurring basis | Fair Value | Equity securities
Assets:
Marketable securities:	25,325,000	6,977,000
Long-term investments:	12,360,000	31,244,000
Fair value on a recurring basis | Fair Value | Auction rate security
Assets:
Long-term investments:	$ 9,300,000	$ 8,100,000