Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lease Cost [Line Items]
Net lease cost	$ 3,348	$ 3,364	$ 6,671	$ 6,829
Other, net [Member]
Lease Cost [Line Items]
Operating lease cost for subleased/assigned properties	544	635	1,041	1,171
Sublease income subleased/assigned properties	(544)	(635)	(1,047)	(1,171)
Occupancy [Member]
Lease Cost [Line Items]
Operating lease cost	3,346	3,357	6,669	6,806
Variable lease costs	$ 2	$ 7	$ 8	$ 23