Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease expense	$ 2,086	$ 3,864
Variable lease expense	620	1,143
Total lease expense	$ 2,706	$ 5,007