Stockholders' Equity (Summary of Activity Related to Stock Option Plans) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Available for Grant, Beginning Balances	4,049,037	7,013,508	2,038,502
Options Outstanding, Number of Shares, Beginning Balances	4,572,952	2,957,754	2,892,130
Shares Available for Grant, Authorized			5,700,000
Options Outstanding, Number of Shares, Granted	642,720	1,803,798	724,994
Options Outstanding, Number of Shares, Exercised	(1,688,774)	(188,552)	(659,370)
Options Outstanding, Number of Shares, Canceled		48
Shares Available for Grant, Expired		(1,160,721)
Shares Available for Grant, Ending Balances	3,406,317	4,049,037	7,013,508
Options Outstanding, Number of Shares, Ending Balances	3,526,898	4,572,952	2,957,754
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options Outstanding, Weighted-Average Exercise Price, Beginning Balances	$ 71.33	$ 66.59	$ 36.11
Options Outstanding, Weighted-Average Exercise Price, Granted	$ 208.94	$ 73.94	$ 154.09
Options Outstanding, Weighted-Average Exercise Price, Exercised	$ 73.75	$ 21.85	$ 29.11
Options Outstanding, Weighted-Average Exercise Price, Canceled		$ 35.95
Options Outstanding, Weighted-Average Exercise Price, Ending Balances		$ 71.33	$ 66.59
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding, Number of Shares, Vested and exercisable	3,526,898
Options Outstanding, Weighted-Average Exercise Price, Vested and exercisable	$ 95.25
Weighted-Average Remaining Contractual Term, Vested and exercisable (in Years)	6 years 1 month 28 days
Aggregate Intrinsic Value, Vested and exercisable	$ 962,570