Fair Value Measurements and the Fair Value Option (Fair Value Option) (Details) (USD $)	6 Months Ended						3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2011 Equity Method Investments [Member]	Jun. 30, 2012 Equity Method Investments [Member] Investment	Dec. 31, 2011 Equity Method Investments [Member]	Jun. 30, 2011 Equity Method Investments [Member] Scenario, Previously Reported [Member]	Jun. 30, 2011 Equity Method Investments [Member] Investment Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Number of Investments				2
Equity Method Investment, Increase in Ownership Percentage			24.00%
Equity Method Investment, Ownership Percentage			48.00%			24.00%
Payments to Acquire Equity Method Investments	$ 49,469,000	$ 73,667,000	$ 7,000,000
Fair Value, Option, Changes in Fair Value, Gain (Loss)		2,000,000					2,000,000
Fair Value, Option, Fair Value Disclosure				$ 27,700,000	$ 27,900,000