Loans - Recorded Investment in Past Due and Non-accruing Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	$ 1,262	$ 2,679
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	5,362	5,300
Total Past Due and Nonaccruals	6,624	7,979
Current	643,002	377,030
Total Gross Loans	649,626	385,009
Construction, Land and Land Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	93
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	542	623
Total Past Due and Nonaccruals	635	623
Current	57,256	39,195
Total Gross Loans	57,891	39,818
Farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due		57
90 Days or More Past Due and Still Accruing	0	0
Total Past Due and Nonaccruals		57
Current	966	966
Total Gross Loans	966	1,023
Commercial Mortgages (Non-Owner Occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	454
90 Days or More Past Due and Still Accruing	0	0
Total Past Due and Nonaccruals	454
Current	79,786	35,343
Total Gross Loans	80,240	35,343
Commercial Mortgages (Owner Occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due		188
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	1,747	2,270
Total Past Due and Nonaccruals	1,747	2,458
Current	72,234	39,367
Total Gross Loans	73,981	41,825
Residential First Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	236	1,546
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	1,941	2,155
Total Past Due and Nonaccruals	2,177	3,701
Current	257,897	190,306
Total Gross Loans	260,074	194,007
Residential Revolving and Junior Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	43	480
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	956	160
Total Past Due and Nonaccruals	999	640
Current	48,307	25,785
Total Gross Loans	49,306	26,425
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due		408
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	110	92
Total Past Due and Nonaccruals	110	500
Current	85,829	42,524
Total Gross Loans	85,939	43,024
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	436
90 Days or More Past Due and Still Accruing	0	0
Nonaccruals	66
Total Past Due and Nonaccruals	502
Current	40,727	3,544
Total Gross Loans	$ 41,229	$ 3,544