Summary of Significant Accounting Policies - Summary of Bank's Actual Capital Amounts and Ratios, and the Regulatory Minimum Ratios (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Accounting Policies [Abstract]
Regulatory, Minimum, Leverage ratio	4.0
Regulatory, Minimum, Common equity tier 1 capital ratio	7.00%
Regulatory, Minimum, Tier 1 capital ratio	8.5
Regulatory, Minimum, Total capital ratio	10.5
Regulatory, Well-Capitalized, Leverage ratio	5.0
Regulatory, Well-Capitalized, Common equity tier 1 capital ratio	6.50%
Regulatory, Well-Capitalized, Tier 1 capital ratio	8.0
Regulatory, Well-Capitalized, Total capital ratio	10.0
Common equity Tier 1 capital	$ 228,838	$ 193,459
Tier 1 capital	297,626	262,247
Total capital	320,957	281,211
Average assets	1,834,814	1,495,726
Risk-weighted assets	$ 1,829,047	$ 1,482,678
Leverage ratio	16.2	17.5
Common equity Tier 1 capital ratio	12.5	13.1
Tier 1 capital ratio	16.3	17.7
Total capital ratio	17.6	19.0