Treasury Stock	3 Months Ended
Mar. 31, 2012
Equity [Abstract]
Treasury Stock	Treasury Stock Stock Repurchase Program Our Board of Directors previously authorized the repurchase of up to $300.0 million of our common stock, $150.0 million in August 2011 and $150.0 million in February 2012, exclusive of any fees, commissions or other expenses. The purchase of stock under the program may be made in the open market or through privately negotiated transactions. The timing, manner, price and amount of any repurchases will be determined by us at our discretion and will depend upon a variety of factors including economic and market conditions, the cash needs and investment opportunities for the business, price, applicable legal requirements and other factors. Our stock repurchase program may be suspended or discontinued at any time. During the three months ended March 31, 2012, we purchased 1.0 million shares of common stock for an aggregate purchase price of $4.5 million, net of an insignificant amount of commissions, for an average price of $4.62. Since inception of the program, we have purchased a total of 29.5 million shares at an aggregate purchase price of $133.4 million, net of $0.6 million of commissions. At March 31, 2012, approximately $166.6 million was available to repurchase common stock pursuant to the stock repurchase program. Shares for Tax Withholding During each of the three months ended March 31, 2012 and 2011, we withheld 0.1 million shares from restricted shares that vested during the respective period to satisfy tax withholding obligations. Minimum tax withholding obligations that arose on the vesting of restricted shares were $0.4 million and $0.7 million for the three months ended March 31, 2012 and 2011, respectively.

Treasury Stock

Stock Repurchase Program

Our Board of Directors previously authorized the repurchase of up to $300.0 million of our common stock, $150.0 million in August 2011 and $150.0 million in February 2012, exclusive of any fees, commissions or other expenses. The purchase of stock under the program may be made in the open market or through privately negotiated transactions. The timing, manner, price and amount of any repurchases will be determined by us at our discretion and will depend upon a variety of factors including economic and market conditions, the cash needs and investment opportunities for the business, price, applicable legal requirements and other factors. Our stock repurchase program may be suspended or discontinued at any time.

During the three months ended March 31, 2012, we purchased 1.0 million shares of common stock for an aggregate purchase price of $4.5 million, net of an insignificant amount of commissions, for an average price of $4.62. Since inception of the program, we have purchased a total of 29.5 million shares at an aggregate purchase price of $133.4 million, net of $0.6 million of commissions. At March 31, 2012, approximately $166.6 million was available to repurchase common stock pursuant to the stock repurchase program.

Shares for Tax Withholding

During each of the three months ended March 31, 2012 and 2011, we withheld 0.1 million shares from restricted shares that vested during the respective period to satisfy tax withholding obligations. Minimum tax withholding obligations that arose on the vesting of restricted shares were $0.4 million and $0.7 million for the three months ended March 31, 2012 and 2011, respectively.