Loans - Schedule of Aging of Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 549,533	$ 545,487
Non-accrual	4,367	4,298
Total past due and non-accrual	5,336	5,646
Total ending loans balance	554,869	551,133
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	739	830
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	228	277
90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	2	241
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,544	135,707
Non-accrual	1,316	1,325
Total past due and non-accrual	1,420	1,407
Total ending loans balance	139,964	137,114
Commercial [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	104	15
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	189,953	194,157
Non-accrual	2,354	2,405
Total past due and non-accrual	2,434	2,591
Total ending loans balance	192,387	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	80	186
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	176,176	173,023
Non-accrual	662	521
Total past due and non-accrual	1,228	1,236
Total ending loans balance	177,404	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	357	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	207	277
Residential Real Estate [Member] | 90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	2	174
Construction & Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	26,516	23,960
Total ending loans balance	26,516	23,960
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	18,344	18,640
Non-accrual	35	47
Total past due and non-accrual	254	412
Total ending loans balance	18,598	19,052
Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	198	$ 365
Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Loans Total Past Due	$ 21