Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Operating Leases
Operating lease right-of-use assets	$ 109,916	$ 0	$ 0
Operating lease liabilities	114,040	$ 0	$ 0
Finance Leases
Premises and equipment, net	7,335
Other borrowings	$ 7,432
Weighted-Average Remaining Lease Term
Operating leases	11 years
Finance leases	12 years 1 month 6 days
Weighted-Average Discount Rate
Operating leases	3.45%
Finance leases	4.48%