Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	Sep. 30, 2023	Jun. 30, 2023	Jan. 01, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit/loan losses	$ 6,691,000	$ 6,559,000		$ 6,838,000	$ 7,008,000	$ 7,268,000	$ 7,618,000
Retained earnings	94,614,000			$ 86,502,000
Allowance for credit losses, available for sale debt securities	0
Held to maturity security, allowance for credit loss	$ 0
Accounting Standards Update 2016-13 [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit/loan losses			$ 6,279,000
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Change in accounting principle, accounting standards update, adopted	true
Net of tax related to loans			442,000
Unfunded commitments			390,000
Accounting Standards Update 2016-13 [Member] | Cumulative Effect of Adoption [Memnber]
Summary Of Significant Accounting Policies [Line Items]
Retained earnings			$ 52,000
Accounting Standards Update 2022-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Change in accounting principle, accounting standards update, adopted	true
Maximum [Member] | Commercial Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit/loan losses	$ 500,000