Allowance for Loan Losses - Past Due Information of Loan Portfolio by Class (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Impaired [Line Items]
Total Loans	$ 445,924	$ 420,779
Accruing Loans 90 or More Days Past Due	0	0
Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	526	914
Loans 90 Days or More Past Due and Non - Accrual [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	861	972
Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	1,387	1,886
Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	444,537	418,893
Real Estate - Commercial [Member]
Financing Receivable Impaired [Line Items]
Total Loans	154,734	150,543
Accruing Loans 90 or More Days Past Due	0	0
Real Estate - Commercial [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	127	127
Real Estate - Commercial [Member] | Loans 90 Days or More Past Due and Non - Accrual [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	286	292
Real Estate - Commercial [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	413	419
Real Estate - Commercial [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	154,321	150,124
Other Real Estate Construction [Member]
Financing Receivable Impaired [Line Items]
Total Loans	42,713	28,275
Accruing Loans 90 or More Days Past Due	0	0
Other Real Estate Construction [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	42,713	28,275
Real Estate 1 - 4 Family Construction [Member]
Financing Receivable Impaired [Line Items]
Total Loans	8,927	8,424
Accruing Loans 90 or More Days Past Due	0	0
Real Estate 1 - 4 Family Construction [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	8,927	8,424
Real Estate - Residential [Member]
Financing Receivable Impaired [Line Items]
Total Loans	84,729	79,324
Accruing Loans 90 or More Days Past Due	0	0
Real Estate - Residential [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	211	559
Real Estate - Residential [Member] | Loans 90 Days or More Past Due and Non - Accrual [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	163	337
Real Estate - Residential [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	374	896
Real Estate - Residential [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	84,355	78,428
Home Equity [Member]
Financing Receivable Impaired [Line Items]
Total Loans	52,666	51,003
Accruing Loans 90 or More Days Past Due	0	0
Home Equity [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	19
Home Equity [Member] | Loans 90 Days or More Past Due and Non - Accrual [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	31	33
Home Equity [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	50	33
Home Equity [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	52,616	50,970
Other Loans [Member]
Financing Receivable Impaired [Line Items]
Total Loans	5,393	5,496
Accruing Loans 90 or More Days Past Due	0	0
Other Loans [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	5,393	5,496
Paycheck Protection Program [Member]
Financing Receivable Impaired [Line Items]
Total Loans	7,599	15,100
Accruing Loans 90 or More Days Past Due	0	0
Paycheck Protection Program [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	9
Paycheck Protection Program [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	9
Paycheck Protection Program [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	7,590	15,100
Commercial Loan [Member]
Financing Receivable Impaired [Line Items]
Total Loans	80,123	73,035
Accruing Loans 90 or More Days Past Due	0	0
Commercial Loan [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	122	201
Commercial Loan [Member] | Loans 90 Days or More Past Due and Non - Accrual [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	381	310
Commercial Loan [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	503	511
Commercial Loan [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	79,620	72,524
Consumer Loans [Member]
Financing Receivable Impaired [Line Items]
Total Loans	9,040	9,579
Accruing Loans 90 or More Days Past Due	0	0
Consumer Loans [Member] | Loans 30-89 Days Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	38	27
Consumer Loans [Member] | Financial Asset, Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	38	27
Consumer Loans [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable Impaired [Line Items]
Total Past Due Loans	$ 9,002	$ 9,552