Cash, Cash Equivalents, and Investments - Textuals (Details) (USD $)	3 Months Ended	9 Months Ended				3 Months Ended	9 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2011 Year month investments	Sep. 30, 2011 Year issuers day month investments	Sep. 30, 2010	Dec. 31, 2010 investments	Apr. 08, 2010	Sep. 30, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies	Sep. 30, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies	Sep. 30, 2010 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies	Sep. 30, 2011 Fair Value, Measurements, Nonrecurring [Member] Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Fair Value, Measurements, Nonrecurring [Member] Cost Method Investee, Privately Held Companies	Sep. 30, 2011 Cost Method Investee, Privately Held Companies	Sep. 30, 2010 Cost Method Investee, Privately Held Companies	Sep. 30, 2011 Cost Method Investee, Privately Held Companies	Sep. 30, 2010 Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Cost Method Investee, Privately Held Companies
Total investments In unrealized loss position	157	157		73
Decrease in Restricted Cash	$ 2,300,000	$ 30,000,000
Business Acquisition, Cash Value of Unvested Restricted Shares	2,300,000	2,300,000			10,700,000
Business Acquisition, Payments for Restricted Shares That Have Vested	8,400,000	8,400,000
Vesting period for restricted shares (in months)	12	12
Minority equity investment									400,000	800,000	51,000,000		51,000,000		22,100,000
Investment in privately-held companies											23,800,000	4,600,000	32,500,000	9,800,000
Cost Method Investment, Other than Temporary Impairment						1,800,000	1,800,000	0
Gain (loss) on equity investments		$ (982,000)	$ 3,232,000								$ (1,100,000)		$ (982,000)	$ 3,232,000