Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2012

Stockholders' Equity Note [Abstract]

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

The following sets forth the change in the number of shares of Class A common stock outstanding during the fiscal years ended December 31, 2012 and 2011:

	December 31,
	2012		2011
Shares outstanding as of beginning of period	92,433		91,725
Shares issued as part of equity-based compensation plans and the ESPP, net of shares surrendered	1,119		708
Shares repurchased into treasury stock	(9,157	)	—
Shares outstanding as of end of period	84,395		92,433