Loans - Schedule of Aging of Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 625,147	$ 545,487
Non-accrual	4,056	4,298
Total past due and non-accrual	4,461	5,646
Total ending loans balance	629,608	551,133
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	289	830
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	71	277
90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	45	241
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	210,202	135,707
Non-accrual	1,295	1,325
Total past due and non-accrual	1,445	1,407
Total ending loans balance	211,647	137,114
Commercial [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	125	15
Commercial [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	25
Commercial [Member] | 90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due		67
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	192,344	194,157
Non-accrual	2,113	2,405
Total past due and non-accrual	2,149	2,591
Total ending loans balance	194,493	196,748
Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	36	186
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	175,507	173,023
Non-accrual	619	521
Total past due and non-accrual	749	1,236
Total ending loans balance	176,256	174,259
Residential Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	67	264
Residential Real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	18	277
Residential Real Estate [Member] | 90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	45	174
Construction & Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	28,875	23,960
Total ending loans balance	28,875	23,960
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	18,219	18,640
Non-accrual	29	47
Total past due and non-accrual	118	412
Total ending loans balance	18,337	19,052
Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	61	$ 365
Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	$ 28