Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2011

Stockholders' Equity

Schedule of change in the number of shares of Class A common stock

	December 31,
	2011		2010
Shares outstanding as of beginning of period		91,725		93,883
Shares issued as part of equity-based compensation plans and the ESPP, net of shares surrendered		708		461
Shares repurchased into treasury stock		—		(2,619	)
Shares outstanding as of end of period		92,433		91,725