Stockholders' Equity

3 Months Ended

Mar. 31, 2014

Stockholders' Equity Note [Abstract]

Stockholders' Equity

Stockholders’ Equity

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, 2014 and during the fiscal year ended December 31, 2013:

	Three Months Ended		Twelve Months Ended
	March 31, 2014		December 31, 2013
Shares outstanding as of beginning of period	85.2		84.4
Shares issued as part of equity-based compensation plans and the Employee    Stock Purchase Plan ("ESPP"), net of restricted stock units surrendered	1.0		1.1
Common stock repurchases	(2.0	)	(0.3	)
Shares outstanding as of end of period	84.2		85.2

On December 5, 2013, our board of directors approved an extension of our existing stock repurchase program to December 31, 2014. The program, originally announced in May 2010, was due to expire on December 31, 2013. Under the program, we are authorized to repurchase, from time to time through open market purchases or otherwise, shares of our outstanding common stock in an aggregate amount up to $200.0 million. During the first quarter of 2014, we repurchased approximately 2.0 million shares at an aggregate cost of $29.5 million. As of March 31, 2014, we had $75.0 million available for potential repurchases under the program. Purchases made during the first quarter of 2014 were funded by cash flows from operations.

During 2013, we repurchased 50,000 shares at an aggregate cost of $0.8 million.