Common Stock Repurchase Programs	6 Months Ended
Jun. 30, 2013
Equity [Abstract]
Common Stock Repurchase Programs	13. Common Stock Repurchase Programs On August 31, 2012, the board of directors approved the repurchase of $100 million of outstanding common stock. This authorization expires in February 2014. Under this publicly announced plan, we repurchased 1.3 million shares for an aggregate purchase price of $22.9 million during the year ended December 31, 2012. We repurchased 0.2 and 0.4 million shares for an aggregate purchase price of $5.0 and $10.0 million during the three and six months ended June 30, 2013. Our employees have the option to surrender shares of common stock to satisfy their tax withholding obligations that arise on the vesting of RSUs. In addition, certain employees can surrender shares to satisfy the exercise price of certain stock options and any tax withholding obligations incurred in connection with such exercises. Employees surrendered 0.1 and 0.3 million shares for an aggregate purchase price of $1.3 and $7.8 million for the three and six months ended June 30, 2013, respectively, and 0.4 and 0.5 million shares for an aggregate purchase price of $7.8 and $9.5 million for the three and six months ended June 30, 2012, respectively. These repurchased shares are recorded as treasury stock and are accounted for under the cost method thereby reducing shares outstanding. None of these repurchased shares of common stock have been cancelled. Our buyback program is limited by SEC regulations and is subject to compliance with our insider trading policy.

13. Common Stock Repurchase Programs

On August 31, 2012, the board of directors approved the repurchase of $100 million of outstanding common stock. This authorization expires in February 2014. Under this publicly announced plan, we repurchased 1.3 million shares for an aggregate purchase price of $22.9 million during the year ended December 31, 2012. We repurchased 0.2 and 0.4 million shares for an aggregate purchase price of $5.0 and $10.0 million during the three and six months ended June 30, 2013.

Our employees have the option to surrender shares of common stock to satisfy their tax withholding obligations that arise on the vesting of RSUs. In addition, certain employees can surrender shares to satisfy the exercise price of certain stock options and any tax withholding obligations incurred in connection with such exercises. Employees surrendered 0.1 and 0.3 million shares for an aggregate purchase price of $1.3 and $7.8 million for the three and six months ended June 30, 2013, respectively, and 0.4 and 0.5 million shares for an aggregate purchase price of $7.8 and $9.5 million for the three and six months ended June 30, 2012, respectively.

These repurchased shares are recorded as treasury stock and are accounted for under the cost method thereby reducing shares outstanding. None of these repurchased shares of common stock have been cancelled. Our buyback program is limited by SEC regulations and is subject to compliance with our insider trading policy.