Commitments and Letters of Credit - Notional Amount of Commitments and Letter of Credit Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Commitments Net	$ 76	$ 71	$ 223
Commitments to extend credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	2,353,991	2,097,628
Financial standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	18,824	15,988
Performance standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	10,663	16,864
Commercial letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 975	$ 783