Summary of Significant Accounting Policies - Recently Issued and Adopted Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	$ 43,099		$ 0
Operating lease liabilities	$ 44,963
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets		$ 43,500
Operating lease liabilities		$ 45,500