Loans - Internal Risk Ratings (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	$ 1,056,733	$ 924,503
Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	286,127	293,913
Commercial mortgages (non-owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	282,378	196,143
Construction, land and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	132,502	126,010
Commercial mortgages (owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	76,225	82,829
Residential revolving and junior mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	29,051	31,893
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	187,219	181,730
Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	56,788
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	6,443	11,985
Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	942,565	912,179
Pass | Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	280,760	290,322
Pass | Commercial mortgages (non-owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	236,058	195,584
Pass | Construction, land and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	103,472	123,916
Pass | Commercial mortgages (owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	64,993	81,936
Pass | Residential revolving and junior mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	28,140	31,084
Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	166,650	177,608
Pass | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	56,788
Pass | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	5,704	11,729
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	95,293	3,615
Special Mention | Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	1,890	1,091
Special Mention | Commercial mortgages (non-owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	40,084
Special Mention | Construction, land and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	26,764
Special Mention | Commercial mortgages (owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	10,893	149
Special Mention | Residential revolving and junior mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	514	86
Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	14,607	2,289
Special Mention | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	541
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	18,875	8,709
Substandard | Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	3,477	2,500
Substandard | Commercial mortgages (non-owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	6,236	559
Substandard | Construction, land and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	2,266	2,094
Substandard | Commercial mortgages (owner occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	339	744
Substandard | Residential revolving and junior mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	397	723
Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	5,962	1,833
Substandard | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Receivables	$ 198	$ 256