Regulatory Matters - Schedule of Regulatory Capital Ratios Under the Basel III Regulatory Capital Framework (Detail) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Ratio	0.1962	0.1929
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.185	0.1822
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.185	0.1822
Leverage Ratio, Actual Ratio	0.1206	0.1096
Consolidated [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Amount	$ 1,697,999	$ 1,586,888
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,601,361	1,498,731
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,601,361	1,498,731
Leverage Ratio, Actual Amount	$ 1,601,361	$ 1,498,731
Total Capital to Risk-Weighted Assets, Actual Ratio	0.1962	0.1929
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.185	0.1822
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.185	0.1822
Leverage Ratio, Actual Ratio	0.1206	0.1096
Consolidated [Member] | Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 865,590	$ 822,497
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 519,354	$ 493,498
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	0.10	0.10
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	0.06	0.06
Consolidated [Member] | Minimum [Member] | Basel III Fully Phased-In [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 908,870	$ 863,622
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	735,752	699,122
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	605,913	575,748
Leverage Ratio, Minimum Capital Required	$ 346,236	$ 546,983
Total Capital to Risk-Weighted Assets, Minimum Capital Required	0.105	0.105
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	0.085	0.085
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	0.07	0.07
Leverage Ratio, Minimum Capital Required, Ratio	0.04	0.04
Parent Company [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Amount	$ 1,518,365	$ 1,442,902
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,421,727	1,354,745
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,421,727	1,354,745
Leverage Ratio, Actual Amount	$ 1,421,727	$ 1,354,745
Total Capital to Risk-Weighted Assets, Actual Ratio	0.1759	0.1758
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1647	0.165
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1647	0.165
Leverage Ratio, Actual Ratio	0.1075	0.0995
Parent Company [Member] | Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 863,372	$ 820,819
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	690,698	656,655
Common Equity Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	561,192	533,532
Leverage Ratio, Required To Be Considered Well Capitalized, Amount	$ 431,686	$ 681,107
Total Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	0.10	0.10
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	0.08	0.08
Common Equity Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized , Ratio	0.065	0.065
Leverage Ratio, Required To Be Considered Well Capitalized , Ratio	0.05	0.05
Parent Company [Member] | Minimum [Member] | Basel III Fully Phased-In [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 906,541	$ 861,860
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	733,866	697,696
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	604,361	574,573
Leverage Ratio, Minimum Capital Required	$ 345,349	$ 544,886
Total Capital to Risk-Weighted Assets, Minimum Capital Required	0.105	0.105
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	0.085	0.085
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	0.07	0.07
Leverage Ratio, Minimum Capital Required, Ratio	0.04	0.04