Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Operating Leases
Operating lease right-of-use assets	$ 106,222	$ 0	$ 0
Operating lease liabilities	110,596	$ 0	$ 0
Finance Leases
Premises and equipment, net	7,503
Other borrowings	$ 7,646
Weighted-Average Remaining Lease Term (in Years)
Operating leases	10 years 10 months 24 days
Finance leases	11 years 8 months 12 days
Weighted-Average Discount Rate
Operating leases	3.45%
Finance leases	4.42%