Fair Value Measurements (Details) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings $ 6,081,000 $ 15,920,000 $ 6,081,000 $ 15,920,000  
Cash and Cash Equivalents, Fair Value Disclosure 607,457,000   607,457,000   750,004,000
Short-term Investments 3,952,000   3,952,000    
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High 17,600,000   17,600,000    
Liabilities, Fair Value Disclosure 7,325,000   7,325,000   13,218,000
Fair Value, Inputs, Level 3 [Member]
         
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Liabilities, Fair Value Disclosure 6,081,000   6,081,000   11,230,000
Fair Value, Inputs, Level 2 [Member]
         
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Liabilities, Fair Value Disclosure 1,244,000   1,244,000   1,988,000
F-Tuan JV [Member]
         
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cost Method Investments $ 128,074,000   $ 128,074,000