Loans - Schedule of Aging of Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 491,572	$ 471,722
Nonaccrual	5,967	1,449
Total Past Due and Nonaccrual	6,529	3,246
Total ending loans balance	498,101	474,968
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	466	1,423
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	27	139
90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	69	235
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	139,066	133,630
Nonaccrual	2,072	425
Total Past Due and Nonaccrual	2,219	638
Total ending loans balance	141,285	134,268
Commercial [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	147	151
Commercial [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		62
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	165,328	158,504
Nonaccrual	3,387	497
Total Past Due and Nonaccrual	3,484	971
Total ending loans balance	168,812	159,475
Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	58	435
Commercial Real Estate [Member] | 90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	39	39
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	150,426	142,926
Nonaccrual	478	490
Total Past Due and Nonaccrual	700	1,563
Total ending loans balance	151,126	144,489
Residential Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	174	816
Residential Real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18	61
Residential Real Estate [Member] | 90 Days Plus Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	30	196
Construction & Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	20,705	23,428
Total ending loans balance	20,705	23,428
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	16,047	13,234
Nonaccrual	30	37
Total Past Due and Nonaccrual	126	74
Total ending loans balance	16,173	13,308
Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	87	21
Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 9	$ 16