Summary of Significant Accounting Policies (Changes in Accounting Pronouncements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 524,439	$ 62,026	$ 337,776
Net cash (used in) provided by financing activities	(393,982)	6,055,467	302,857
Retained earnings (deficit)	(5,688,281)	(2,341,215)
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	527,643	84,005	372,964
Net cash (used in) provided by financing activities	(397,186)	6,033,488	267,669
Effect of Adoption | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	3,204	21,979	35,188
Net cash (used in) provided by financing activities	(3,204)	$ (21,979)	$ (35,188)
Pro Forma | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease to income tax benefit	700
Accounting Standards Update 2016-16 | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Current deferred charge	34,300
Non-current deferred charge	348,800
Accounting Standards Update 2016-16 | New Accounting Pronouncement, Early Adoption, Effect | Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings (deficit)	$ 25,000