Nature of Business and Accounting Policies Nature of Business and Accounting Policies - Intra-Equity Transfers (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets	$ 1,880,125,000	$ 1,734,542,000
Accounting Standards Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets	204,700,000
Accumulated Deficit | Accounting standards update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	$ 0