Leases - Schedule of Components of Occupancy Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease Cost [Line Items]
Net lease cost	$ 3,465	$ 2,869
Other, net [Member]
Lease Cost [Line Items]
Operating lease cost for subleased/assigned properties	536	573
Sublease income subleased/assigned properties	(536)	(573)
Occupancy [Member]
Lease Cost [Line Items]
Operating lease cost	3,449	2,745
Variable lease costs	$ 16	$ 124