Commitments and Contingencies (Details) (USD $)	1 Months Ended	0 Months Ended
Jul. 31, 2010	May 22, 2006	Sep. 10, 2009 Positive Outcome of Litigation [Member]
Gain Contingencies [Line Items]
Recovery amount sought by plaintiffs		$ 0
Proceeds from derivative litigation settlement			18,900,000
Adjustments to additional paid-in capital, derivative settlement			2,500,000
Gain related to litigation settlement			16,400,000
Payments for legal settlements	$ 173,000,000

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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