Premises and Equipment - Future Minimum Lease Payments Under Non-cancellable Leases (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Property Plant And Equipment [Abstract]
Operating Leases, 2020	$ 6,517
Operating Leases, 2021	5,948
Operating Leases, 2022	5,177
Operating Leases, 2023	4,649
Operating Leases, 2024	4,164
Operating Leases, 2025 and thereafter	46,617
Operating Leases, Total lease payments	73,072
Operating Leases, Less: interest	(16,559)
Operating Leases, Present value of lease liabilities	56,513
Finance Leases, 2020	851
Finance Leases, 2021	855
Finance Leases, 2022	873
Finance Leases, 2023	885
Finance Leases, 2024	890
Finance Leases, 2025 and thereafter	4,638
Finance Leases, Total lease payments	8,992
Finance Leases, Less: interest	(3,414)
Finance Leases, Present value of lease liabilities	5,578
2020	7,368
2021	6,803
2022	6,050
2023	5,534
2024	5,054
2025 and thereafter	51,255
Total lease payments	82,064
Less: interest	(19,973)
Present value of lease liabilities	$ 62,091