Debt	9 Months Ended
Sep. 30, 2014
Debt Disclosure [Abstract]
Debt	Debt Senior Bank Debt The Company has a $1.25 billion senior unsecured revolving credit facility (the "credit facility") which matures in April 2018. As of September 30, 2014, there were no outstanding borrowings. On April 15, 2014, the Company entered into a $250.0 million five-year senior unsecured term loan. The Company pays interest at specified rates (based on either the LIBOR rate or the prime rate as in effect from time to time). Subject to certain conditions, the Company may borrow up to an additional $100.0 million. The credit facility and term loan contain financial covenants with respect to leverage and interest coverage, as well as customary affirmative and negative covenants, including limitations on priority indebtedness, liens, cash dividends, asset dispositions, fundamental corporate changes and certain customary events of default. Senior Notes On February 11, 2014, the Company sold $400.0 million aggregate principal amount of 4.25% senior notes due 2024 (the “2024 senior notes”). The unsecured 2024 senior notes pay interest semi-annually and may be redeemed at any time, in whole or in part, at a make-whole redemption price plus accrued and unpaid interest. In addition to customary event of default provisions, the underlying indenture limits the Company's ability to consolidate, merge or sell all or substantially all of its assets, and to create certain liens. Convertible Securities On February 13, 2014, the Company delivered a notice to redeem all of its outstanding 2006 junior convertible securities. In lieu of redemption, substantially all holders of the 2006 junior convertible securities elected to convert their securities into a defined number of shares. The Company issued 1.9 million shares of its common stock and recognized an expense of $18.8 million in the three months ended March 31, 2014, which is included in Imputed interest expense and contingent payment arrangements. All of the Company's 2006 junior convertible securities have been canceled and retired.

Debt

Senior Bank Debt

The Company has a $1.25 billion senior unsecured revolving credit facility (the "credit facility") which matures in April 2018. As of September 30, 2014, there were no outstanding borrowings.

On April 15, 2014, the Company entered into a $250.0 million five-year senior unsecured term loan. The Company pays interest at specified rates (based on either the LIBOR rate or the prime rate as in effect from time to time). Subject to certain conditions, the Company may borrow up to an additional $100.0 million.

The credit facility and term loan contain financial covenants with respect to leverage and interest coverage, as well as customary affirmative and negative covenants, including limitations on priority indebtedness, liens, cash dividends, asset dispositions, fundamental corporate changes and certain customary events of default.

Senior Notes

On February 11, 2014, the Company sold $400.0 million aggregate principal amount of 4.25% senior notes due 2024 (the “2024 senior notes”). The unsecured 2024 senior notes pay interest semi-annually and may be redeemed at any time, in whole or in part, at a make-whole redemption price plus accrued and unpaid interest. In addition to customary event of default provisions, the underlying indenture limits the Company's ability to consolidate, merge or sell all or substantially all of its assets, and to create certain liens.

Convertible Securities

On February 13, 2014, the Company delivered a notice to redeem all of its outstanding 2006 junior convertible securities. In lieu of redemption, substantially all holders of the 2006 junior convertible securities elected to convert their securities into a defined number of shares. The Company issued 1.9 million shares of its common stock and recognized an expense of $18.8 million in the three months ended March 31, 2014, which is included in Imputed interest expense and contingent payment arrangements. All of the Company's 2006 junior convertible securities have been canceled and retired.