Loans - Summary of Major Classifications of Loans (Detail) - USD ($) $ in Thousands		Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	[1]	$ 401,071		$ 397,714
Net deferred loan costs		545		854
Allowance for credit losses for loans		(3,966)	$ (3,871)	(3,734)	$ (3,614)	$ (3,643)	$ (3,203)
Total loans, net of deferred loan costs and allowance for credit losses		397,650		394,834
Commercial [Member] | Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		233,924		231,893
Commercial [Member] | Other Commercial Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		50,307		47,898
Residential Real Estate [Member] | First Mortgage [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		96,202		97,747
Residential Real Estate [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		959		359
Consumer [Member] | Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		19,591		19,683
Consumer [Member] | Other Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross		$ 88		$ 134

[1] Totals do not include accrued interest receivable, which was $1.1 million at both September 30, 2024 and December 31, 2023, and which is recorded separately on the Company’s Consolidated Balance Sheets.