Leases - Summary of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 6,752	$ 17,915
Variable lease expense	1,328	3,535
Short-term lease expense	147	438
Sublease income	(441)	(1,274)
Total net lease expense	$ 7,786	$ 20,614