Summary of Significant Accounting Policies - Summary of Bank's Actual Capital Amounts and Ratios, and the Regulatory Minimum Ratios (Detail) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Accounting Policies [Abstract]
Regulatory, Minimum, Leverage ratio	[1]	0.04
Regulatory, Minimum, Common equity tier 1 capital ratio	[2]	4.50%
Regulatory, Minimum, tier 1 Buffer capital ratio	[3]	6.00%
Regulatory, Minimum, Total capital ratio	[3]	0.08
Regulatory, Well-Capitalized, Leverage ratio	[1]	0.05
Regulatory, Well-Capitalized, Common equity tier 1 capital ratio	[2]	6.50%
Regulatory, Well-Capitalized, tier 1 capital ratio	[3]	0.08
Regulatory, Well-Capitalized, Total capital ratio	[3]	0.10
Common equity Tier 1 capital		$ 337,738	$ 322,229
Tier 1 capital		479,652	391,016
Total capital		511,144	422,139
Average assets		2,485,311	2,493,857
Risk-weighted assets		$ 2,455,409	$ 2,429,349
Leverage ratio	[1]	0.193	0.157
Common equity tier 1 capital ratio	[2]	0.138	0.133
Tier 1 capital ratio	[3]	0.195	0.161
Total capital ratio	[3]	0.208	0.174

[1] Calculated by dividing Tier 1 capital by average assets.

[2] Calculated by subtracting preferred stock or non-controlling interest from Tier 1 capital and dividing by risk-weighted assets.

[3] Calculated by dividing Tier 1 or total capital by risk-weighted assets.