Loans - Schedule of Analysis of Past due Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	$ 330,359	$ 310,433
Total Loans	331,598	312,370
Nonaccrual Loans	$ 1,287	$ 2,013
Total non-accrual loans to total loans	0.39%	0.64%
Total non-accrual loans to total assets	0.25%	0.47%
Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	$ 189,050	$ 178,702
Total Loans	189,291	178,882
Nonaccrual Loans		180
Commercial Land Development [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	1,492	1,623
Total Loans	1,492	1,623
Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	46,151	33,924
Total Loans	46,184	34,072
Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	68,147	63,854
Total Loans	68,968	65,450
Nonaccrual Loans	1,151	1,690
Residential Real Estate Construction [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	2,954	2,041
Total Loans	2,954	2,041
Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	22,204	29,678
Total Loans	22,348	29,691
Nonaccrual Loans	136	143
Consumer Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Current Loans	361	611
Total Loans	361	611
Loans Past Due 30-89 Days [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	1,079	1,220
Loans Past Due 30-89 Days [Member] \| Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	241
Loans Past Due 30-89 Days [Member] \| Commercial Other [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	33	148
Loans Past Due 30-89 Days [Member] \| Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	684	1,059
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]
Past Due	121	13
Loans Past Due 90+ Days [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	160	717
Loans Past Due 90+ Days [Member] \| Commercial Real Estate [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due		180
Loans Past Due 90+ Days [Member] \| Residential Real Estate First Mortgages [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	137	$ 537
Loans Past Due 90+ Days [Member] \| Consumer Home Equity and Lines of Credit [Member]
Loans, Notes and Certificates, and Loan Servicing Rights [Line Items]
Past Due	$ 23

Loans and leases receivable, ratio of nonperforming loans to all assets.

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Amount of financing receivable not past due.

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