Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lease Cost [Line Items]
Net lease cost	$ 3,364	$ 2,687	$ 6,829	$ 5,556
Other, net [Member]
Lease Cost [Line Items]
Operating lease cost for subleased/assigned properties	635	583	1,171	1,156
Sublease income subleased/assigned properties	(635)	(583)	(1,171)	(1,156)
Occupancy [Member]
Lease Cost [Line Items]
Operating lease cost	3,357	2,656	6,806	5,401
Variable lease costs	$ 7	$ 31	$ 23	$ 155