Regulatory Matters - Schedule of Regulatory Capital Ratios Under the Basel III Regulatory Capital Framework (Detail) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Ratio	0.20	0.1962
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1883	0.185
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1883	0.185
Leverage Ratio, Actual Ratio	0.1249	0.1206
Consolidated [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk-Weighted Assets, Actual Amount	$ 1,838,118	$ 1,697,999
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,731,116	1,601,361
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,731,116	1,601,361
Leverage Ratio, Actual Amount	$ 1,731,116	$ 1,601,361
Total Capital to Risk-Weighted Assets, Actual Ratio	0.20	0.1962
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1883	0.185
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1883	0.185
Leverage Ratio, Actual Ratio	0.1249	0.1206
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	$ 919,146	$ 865,590
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	$ 551,487	$ 519,354
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	$ 965,103	$ 908,870
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	781,274	735,752
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	643,402	605,913
Leverage Ratio, Minimum Capital Required	$ 367,658	$ 346,236
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	$ 1,698,590	$ 1,518,365
Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,591,588	1,421,727
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Amount	1,591,588	1,421,727
Leverage Ratio, Actual Amount	$ 1,591,588	$ 1,421,727
Total Capital to Risk-Weighted Assets, Actual Ratio	0.1853	0.1759
Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1736	0.1647
Common Equity Tier1 Capital to Risk-Weighted Assets, Actual Ratio	0.1736	0.1647
Leverage Ratio, Actual Ratio	0.1153	0.1075
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	$ 916,689	$ 863,372
Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	733,351	690,698
Common Equity Tier1 Capital to Risk-Weighted Assets, Required To Be Considered Well Capitalized, Amount	595,848	561,192
Leverage Ratio, Required To Be Considered Well Capitalized, Amount	$ 458,345	$ 431,686
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	$ 962,524	$ 906,541
Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	779,186	733,866
Common Equity Tier1 Capital to Risk-Weighted Assets, Minimum Capital Required	641,682	604,361
Leverage Ratio, Minimum Capital Required	$ 366,676	$ 345,349
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