Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Sep. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Restricted cash		$ 868	$ 0
Operating lease right-of-use assets	$ 39,900	142,110
Operating lease liability	42,100	$ 158,734
Reclassification of deferred and prepaid rents to right of use assets	$ 2,200