Summary of Significant Accounting Policies - Recent Accounting Standards (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts payable and accrued expenses		$ 360,279	$ 141,290
Deferred revenue		54,741	26,919
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts payable and accrued expenses			$ (7,500)
Deferred revenue		$ 7,500
Accounting Standards Update 2016-02 | Scenario, Forecast | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets	$ 200,000
Lease liabilities	200,000
Accounting Standards Update 2016-02 | Scenario, Forecast | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets	300,000
Lease liabilities	$ 300,000