Loans - Schedule of Analysis of Past due Loans (Detail) - USD ($) $ in Thousands		Sep. 30, 2024	Dec. 31, 2023
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross	[1]	$ 401,071	$ 397,714
Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		233,924	231,893
Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		50,307	47,898
Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		96,202	97,747
Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		959	359
Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		19,591	19,683
Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		88	134
Loans Past Due 30-89 Days [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		12	378
Loans Past Due 30-89 Days [Member] | Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	79
Loans Past Due 30-89 Days [Member] | Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Loans Past Due 30-89 Days [Member] | Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		7	299
Loans Past Due 30-89 Days [Member] | Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Loans Past Due 30-89 Days [Member] | Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		5	0
Loans Past Due 30-89 Days [Member] | Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Loans Past Due 90+ Days [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		371	395
Loans Past Due 90+ Days [Member] | Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	343
Loans Past Due 90+ Days [Member] | Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Loans Past Due 90+ Days [Member] | Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		315	52
Loans Past Due 90+ Days [Member] | Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Loans Past Due 90+ Days [Member] | Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		56	0
Loans Past Due 90+ Days [Member] | Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Total Past Due [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		383	773
Total Past Due [Member] | Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	422
Total Past Due [Member] | Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Total Past Due [Member] | Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		322	351
Total Past Due [Member] | Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Total Past Due [Member] | Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		61	0
Total Past Due [Member] | Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		0	0
Current Loans [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		400,688	396,941
Current Loans [Member] | Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		233,924	231,471
Current Loans [Member] | Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		50,307	47,898
Current Loans [Member] | Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		95,880	97,396
Current Loans [Member] | Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		959	359
Current Loans [Member] | Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Loans, gross		19,530	19,683
Current Loans [Member] | Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [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.