Loans - Recorded Investment in Past Due and Non-accruing Loans (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	$ 1,502	$ 917
90 Days or More Past Due and Still Accruing	14	19
Nonaccruals	1,954	2,754
Total Past Due and Nonaccruals	3,470	3,690
Current	294,584	246,641
Total Gross Loans	298,054	250,331
Construction, Land and Land Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	64	65
Nonaccruals	669	854
Total Past Due and Nonaccruals	733	919
Current	42,315	30,920
Total Gross Loans	43,048	31,839
Farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,128	1,262
Total Gross Loans	1,128	1,262
Commercial Mortgages (Non-Owner Occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	20,534	14,626
Total Gross Loans	20,534	14,626
Commercial Mortgages (Owner Occupied)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruals	566	427
Total Past Due and Nonaccruals	566	427
Current	32,760	33,750
Total Gross Loans	33,326	34,177
Residential First Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	1,270	668
Nonaccruals	359	1,083
Total Past Due and Nonaccruals	1,629	1,751
Current	133,638	112,707
Total Gross Loans	135,267	114,458
Residential Revolving and Junior Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	6	108
Nonaccruals	31	76
Total Past Due and Nonaccruals	37	184
Current	25,363	23,861
Total Gross Loans	25,400	24,045
Commercial and Industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	96	16
Nonaccruals	228	311
Total Past Due and Nonaccruals	324	327
Current	33,678	23,611
Total Gross Loans	34,002	23,938
Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	66	60
90 Days or More Past Due and Still Accruing	14	19
Nonaccruals	101	3
Total Past Due and Nonaccruals	181	82
Current	5,168	5,904
Total Gross Loans	$ 5,349	$ 5,986