Commitments and Contingent Liabilities - Notional Amount of Outstanding Commitments (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 2,376,865	$ 2,353,991
Financial standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	17,985	18,824
Performance standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	17,584	10,663
Commercial letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 975	$ 975