Commitments and Contingent Liabilities - Notional Amount of Outstanding Commitments (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 2,423,326	$ 2,517,905
Financial standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	13,504	14,300
Performance standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	16,762	17,194
Commercial letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 555	$ 555