Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2012

Stockholders' Equity Note [Abstract]

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

The following table sets forth the change in the number of shares of our Class A common stock outstanding during the three months ended March 31, 2012 and during the fiscal year ended December 31, 2011:

	Three Months Ended	Twelve Months Ended
	March 31, 2012	December 31, 2011
Shares outstanding as of beginning of period	92,433	91,725
Shares issued as part of equity-based compensation plans and the Employee    Stock Purchase Plan (“ESPP”), net of RSUs surrendered	323	708
Shares outstanding as of end of period	92,756	92,433