Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2011

Stockholders' Equity

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

	Nine Months	Twelve Months
	Ended	Ended
	September 30,	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 Employee Stock Purchase Plan (“ESPP”), net of RSUs surrendered	403	461
Shares repurchased into treasury stock	—	(2,619	)
Shares outstanding as of end of period	92,128	91,725