Long-Term Debt	9 Months Ended
Sep. 30, 2013
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Senior Bank Debt The Company entered into a $1.25 billion senior unsecured revolving credit facility in April 2013 (the "credit facility") which matures in April 2018. As of September 30, 2013, the current outstanding balance under the credit facility is $575.0 million. The credit facility is unsecured and contains financial covenants with respect to leverage and interest coverage, as well as customary affirmative and negative covenants, including limitations on indebtedness, liens, cash dividends, asset dispositions and fundamental corporate changes. Convertible Securities In the second and third quarters of 2013, the Company repurchased $79.5 million principal amount outstanding of its 3.95% senior convertible notes due 2038 (“2008 senior convertible notes”). Subsequent to the repurchases, the Company called the remaining 2008 senior convertible notes ($380.5 million principal amount) for redemption on August 15, 2013 at their principal amount. In lieu of redemption, holders of the 2008 senior convertible notes elected to convert their securities. The Company elected to settle such conversions in cash. In connection with its call and prior repurchases, the Company paid an aggregate of $641.3 million. All of the Company's 2008 senior convertible notes have been canceled and retired.

Long-Term Debt

9 Months Ended

Sep. 30, 2013

Senior Bank Debt

The Company entered into a $1.25 billion senior unsecured revolving credit facility in April 2013 (the "credit facility") which matures in April 2018. As of September 30, 2013, the current outstanding balance under the credit facility is $575.0 million.

The credit facility is unsecured and contains financial covenants with respect to leverage and interest coverage, as well as customary affirmative and negative covenants, including limitations on indebtedness, liens, cash dividends, asset dispositions and fundamental corporate changes.

Convertible Securities

In the second and third quarters of 2013, the Company repurchased $79.5 million principal amount outstanding of its 3.95% senior convertible notes due 2038 (“2008 senior convertible notes”). Subsequent to the repurchases, the Company called the remaining 2008 senior convertible notes ($380.5 million principal amount) for redemption on August 15, 2013 at their principal amount. In lieu of redemption, holders of the 2008 senior convertible notes elected to convert their securities. The Company elected to settle such conversions in cash. In connection with its call and prior repurchases, the Company paid an aggregate of $641.3 million. All of the Company's 2008 senior convertible notes have been canceled and retired.