Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information (Unaudited)
Total revenues		$ 404,875	$ 386,221	$ 347,161	$ 327,504	$ 346,363	$ 329,950	$ 322,802	$ 289,403	$ 1,465,761	$ 1,288,519	$ 1,116,984
Cost of product sales		25,309	6,891	16,058	20,778	15,770	40,804	38,709	30,600
Gross profit		379,566	379,330	331,103	306,726	330,593	289,147	284,093	258,803
Net income (loss)		$ 104,644	$ 464,425	$ 99,211	$ (16,641)	$ 115,935	$ (25,237)	$ 111,852	$ 137,524	$ 651,639	$ 340,074	$ 174,560
Net (loss) income per share-basic (in dollars per share)		$ 2.29	$ 10.20	$ 2.15	$ (0.36)	$ 2.44	$ (0.53)	$ 2.35	$ 2.73	$ 14.17	$ 7.06	$ 3.49
Net (loss) income per share-diluted (in dollars per share)		$ 2.10	$ 9.24	$ 1.91	$ (0.36)	$ 2.17	$ (0.53)	$ 2.10	$ 2.43	$ 12.72	$ 6.28	$ 3.28
Share-based compensation expense charged to operating expenses, net of tax		$ 71,600		$ 27,500	$ 145,700	$ 19,900	$ 122,100
Share-based compensation (benefit)			$ (75,700)					$ (1,400)	$ (39,600)
Proceeds from Sale of Intangible Assets	$ 350,000		$ 350,000							$ 350,000