Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) segment	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Number of business segments | segment	1
Operating lease, right-of-use asset	$ 18,010	$ 20,100
Operating lease liability	$ 19,815	$ 22,100	$ 53,601