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