Loans Receivable, Credit Quality for Loans and the Allowance for Loan Losses - Summary of Aging of Loans Receivable by Loan Portfolio Segments (Detail) - USD ($)
$ in Thousands
Sep. 30, 2015
Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due $ 9,343 $ 12,184
Current 342,965 330,509
Ending balance 352,308 342,693
Recorded Investment Greater Than 90 Days & Accruing 1,020 643
Home Equity Lines of Credit [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 204 598
Current 16,930 17,637
Ending balance 17,134 18,235
Commercial [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 1,424 429
Current 40,969 36,872
Ending balance 42,393 37,301
Commercial Real Estate Non-owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2,183 5,603
Current 105,167 97,823
Ending balance 107,350 103,426
Commercial Real Estate Owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2,882 1,379
Current 68,128 70,178
Ending balance 71,010 71,557
Recorded Investment Greater Than 90 Days & Accruing 980 294
Commercial Real Estate 1-4 Family Investment [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 743 961
Current 24,132 23,838
Ending balance 24,875 24,799
Recorded Investment Greater Than 90 Days & Accruing   132
Commercial Land and Land Development [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 30 231
Current 15,761 11,210
Ending balance 15,791 11,441
Residential Real Estate [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 1,875 2,969
Current 69,137 70,484
Ending balance 71,012 73,453
Recorded Investment Greater Than 90 Days & Accruing 40 214
Consumer [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2 14
Current 2,741 2,467
Ending balance 2,743 2,481
Recorded Investment Greater Than 90 Days & Accruing   3
30-59 Days Past Due [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2,549 1,524
30-59 Days Past Due [Member] | Home Equity Lines of Credit [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 128 103
30-59 Days Past Due [Member] | Commercial [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 17 24
30-59 Days Past Due [Member] | Commercial Real Estate Non-owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   15
30-59 Days Past Due [Member] | Commercial Real Estate Owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 534 621
30-59 Days Past Due [Member] | Commercial Real Estate 1-4 Family Investment [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 478  
30-59 Days Past Due [Member] | Commercial Land and Land Development [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 30 16
30-59 Days Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 1,360 739
30-59 Days Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2 6
60-89 Days Past Due [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 4,275 6,471
60-89 Days Past Due [Member] | Home Equity Lines of Credit [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   59
60-89 Days Past Due [Member] | Commercial [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 1,193 41
60-89 Days Past Due [Member] | Commercial Real Estate Non-owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2,160 5,426
60-89 Days Past Due [Member] | Commercial Real Estate Owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 769  
60-89 Days Past Due [Member] | Commercial Real Estate 1-4 Family Investment [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   515
60-89 Days Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 153 425
60-89 Days Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   5
90 Days and Greater [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 2,519 4,189
90 Days and Greater [Member] | Home Equity Lines of Credit [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 76 436
90 Days and Greater [Member] | Commercial [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 214 364
90 Days and Greater [Member] | Commercial Real Estate Non-owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 23 162
90 Days and Greater [Member] | Commercial Real Estate Owner Occupied [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 1,579 758
90 Days and Greater [Member] | Commercial Real Estate 1-4 Family Investment [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due 265 446
90 Days and Greater [Member] | Commercial Land and Land Development [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   215
90 Days and Greater [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due $ 362 1,805
90 Days and Greater [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment, Past Due [Line Items]    
Total Past Due   $ 3