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