Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lease Cost [Line Items]
Net lease cost	$ 3,324	$ 3,465
Other, net [Member]
Lease Cost [Line Items]
Operating lease cost for subleased/assigned properties	497	536
Sublease income subleased/assigned properties	(502)	(536)
Occupancy [Member]
Lease Cost [Line Items]
Operating lease cost	3,323	3,449
Variable lease costs	$ 6	$ 16