Long-Term Debt	3 Months Ended
Mar. 31, 2012
Long-term Debt, Unclassified [Abstract]
Long-Term Debt	Long-term Debt Senior Convertible Notes As of March 31, 2012, the Company had outstanding $200.0 million aggregate principal amount of zero coupon senior convertible notes due on December 1, 2018 (the “Convertible Notes”). The Convertible Notes were issued in a private placement offering to TCV VII, L.P., TCV VII(A), L.P. and TCV Member Fund, L.P. A general partner of these funds also serves on the Company’s board of directors, and as such, the issuance of the notes was considered a related party transaction. At any time following May 28, 2012, the Company may elect to cause the conversion of the Convertible Notes into shares of the Company’s common stock when specified conditions are satisfied, including that the daily volume weighted average price of the Company’s common stock is equal or greater than $111.54 for at least 50 trading days during a 65 trading day period prior to the conversion date. The Convertible Notes include, among other terms and conditions, limitations on the Company’s ability to pay cash dividends or to repurchase shares of its common stock, subject to specified exceptions. At March 31, 2012 and December 31, 2011, the Company was in compliance with these covenants. Based on quoted market prices of the Company’s publicly traded debt, the fair value of the Convertible Notes as of March 31, 2012 and December 31, 2011 was approximately $218.0 million and $206.5 million, respectively. Senior Notes As of March 31, 2012, the Company also had outstanding $200.0 million aggregate principal amount of 8.50% senior notes due November 15, 2017 (the “8.50% Notes”). Interest on the 8.50% Notes is payable semi-annually at a rate of 8.50% per annum on May 15 and November 15 of each year. The 8.50% Notes include, among other terms and conditions, limitations on the Company’s ability to create, incur, assume or be liable for indebtedness (other than specified types of permitted indebtedness); dispose of assets outside the ordinary course (subject to specified exceptions); acquire, merge or consolidate with or into another person or entity (other than specified types of permitted acquisitions); create, incur or allow any lien on any of its property or assign any right to receive income (except for specified permitted liens); make investments (other than specified types of investments); or pay dividends, make distributions, or purchase or redeem the Company’s equity interests (each subject to specified exceptions). At March 31, 2012 and December 31, 2011, the Company was in compliance with these covenants. Based on quoted market prices, the fair value of the 8.50% Notes as of March 31, 2012 and December 31, 2011 was approximately $218.0 million and $206.5 million, respectively.

Long-term Debt

Senior Convertible Notes

As of March 31, 2012, the Company had outstanding $200.0 million aggregate principal amount of zero coupon senior convertible notes due on December 1, 2018 (the “Convertible Notes”). The Convertible Notes were issued in a private placement offering to TCV VII, L.P., TCV VII(A), L.P. and TCV Member Fund, L.P. A general partner of these funds also serves on the Company’s board of directors, and as such, the issuance of the notes was considered a related party transaction. At any time following May 28, 2012, the Company may elect to cause the conversion of the Convertible Notes into shares of the Company’s common stock when specified conditions are satisfied, including that the daily volume weighted average price of the Company’s common stock is equal or greater than $111.54 for at least 50 trading days during a 65 trading day period prior to the conversion date. The Convertible Notes include, among other terms and conditions, limitations on the Company’s ability to pay cash dividends or to repurchase shares of its common stock, subject to specified exceptions. At March 31, 2012 and December 31, 2011, the Company was in compliance with these covenants.

Based on quoted market prices of the Company’s publicly traded debt, the fair value of the Convertible Notes as of March 31, 2012 and December 31, 2011 was approximately $218.0 million and $206.5 million, respectively.

Senior Notes

As of March 31, 2012, the Company also had outstanding $200.0 million aggregate principal amount of 8.50% senior notes due November 15, 2017 (the “8.50% Notes”). Interest on the 8.50% Notes is payable semi-annually at a rate of 8.50% per annum on May 15 and November 15 of each year.

The 8.50% Notes include, among other terms and conditions, limitations on the Company’s ability to create, incur, assume or be liable for indebtedness (other than specified types of permitted indebtedness); dispose of assets outside the ordinary course (subject to specified exceptions); acquire, merge or consolidate with or into another person or entity (other than specified types of permitted acquisitions); create, incur or allow any lien on any of its property or assign any right to receive income (except for specified permitted liens); make investments (other than specified types of investments); or pay dividends, make distributions, or purchase or redeem the Company’s equity interests (each subject to specified exceptions). At March 31, 2012 and December 31, 2011, the Company was in compliance with these covenants.

Based on quoted market prices, the fair value of the 8.50% Notes as of March 31, 2012 and December 31, 2011 was approximately $218.0 million and $206.5 million, respectively.