Loans - Loans Individually Evaluated for Impairment (Detail) (USD $) | 12 Months Ended |
In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | $13,958 | $13,034 | $20,892 |
Total Unpaid Principal Balance | 17,244 | 32,400 | 41,279 |
Total with no related allowance recorded, Recorded Investment | 6,599 | 11,079 | 17,543 |
Total Recorded Investment | 9,885 | 26,071 | 33,555 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 9,474 | 12,875 | 21,747 |
Total with no related allowance recorded, Income Recognized | 12 | 96 | 1,039 |
Total with no related allowance recorded, Cash Basis Income Recognized | 11 | 106 | 1,115 |
Total with an allocated allowance recorded, Unpaid Principal Balance | 3,286 | 19,366 | 20,387 |
Total with an allocated allowance recorded, Recorded Investment | 3,286 | 14,992 | 16,012 |
Total Allowance for Loan Losses Allocated | 247 | 2,446 | 2,307 |
Total with an allocated allowance recorded, Average Recorded Investment | 8,700 | 17,785 | 23,974 |
Total Average Recorded Investment | 18,174 | 30,660 | 45,721 |
Total with an allocated allowance recorded, Income Recognized | 188 | 385 | 692 |
Total Income Recognized | 200 | 481 | 1,731 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 196 | 402 | 732 |
Total Cash Basis Income Recognized | 207 | 508 | 1,847 |
Residential Construction [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | | 3,208 |
Total with no related allowance recorded, Recorded Investment | | | 1,816 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 821 | 633 | 2,650 |
Total with no related allowance recorded, Income Recognized | | | 35 |
Total with no related allowance recorded, Cash Basis Income Recognized | | | 35 |
Total with an allocated allowance recorded, Unpaid Principal Balance | | 2,515 | 2,883 |
Total with an allocated allowance recorded, Recorded Investment | | 2,515 | 2,882 |
Total Allowance for Loan Losses Allocated | | 62 | 552 |
Total with an allocated allowance recorded, Average Recorded Investment | 925 | 2,868 | 2,691 |
Total with an allocated allowance recorded, Income Recognized | 55 | | 55 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 56 | | 67 |
Other Construction [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 3,952 | 6,564 | 11,604 |
Total with no related allowance recorded, Recorded Investment | 3,849 | 6,564 | 9,649 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 5,102 | 7,507 | 9,334 |
Total with no related allowance recorded, Income Recognized | | 1 | 4 |
Total with no related allowance recorded, Cash Basis Income Recognized | | 1 | 8 |
Total with an allocated allowance recorded, Unpaid Principal Balance | 1,402 | 2,291 | 1,011 |
Total with an allocated allowance recorded, Recorded Investment | 1,402 | 2,291 | 1,011 |
Total Allowance for Loan Losses Allocated | 66 | 414 | 399 |
Total with an allocated allowance recorded, Average Recorded Investment | 2,842 | 2,866 | 3,883 |
Total with an allocated allowance recorded, Income Recognized | 1 | 15 | 42 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 1 | 15 | 43 |
Revolving, Open Ended [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 54 | 110 | |
Total with no related allowance recorded, Recorded Investment | 54 | 110 | |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 42 | 184 | |
Total with no related allowance recorded, Income Recognized | 3 | 4 | |
Total with no related allowance recorded, Cash Basis Income Recognized | 3 | 5 | |
Total with an allocated allowance recorded, Unpaid Principal Balance | 37 | 179 | 575 |
Total with an allocated allowance recorded, Recorded Investment | 37 | 179 | 575 |
Total Allowance for Loan Losses Allocated | 33 | 132 | 121 |
Total with an allocated allowance recorded, Average Recorded Investment | 94 | 377 | 608 |
Total with an allocated allowance recorded, Income Recognized | 3 | 3 | -2 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 4 | 5 | 3 |
First Liens [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | 1,163 | 2,446 |
Total with no related allowance recorded, Recorded Investment | | 1,163 | 2,444 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 774 | 1,751 | 3,943 |
Total with no related allowance recorded, Income Recognized | 6 | 29 | 81 |
Total with no related allowance recorded, Cash Basis Income Recognized | 6 | 33 | 80 |
Total with an allocated allowance recorded, Unpaid Principal Balance | 1,299 | 6,122 | 3,333 |
Total with an allocated allowance recorded, Recorded Investment | 1,299 | 6,122 | 3,333 |
Total Allowance for Loan Losses Allocated | 93 | 460 | 288 |
Total with an allocated allowance recorded, Average Recorded Investment | 2,474 | 5,167 | 3,118 |
Total with an allocated allowance recorded, Income Recognized | 65 | 272 | 157 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 69 | 255 | 184 |
Junior Liens [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 108 | 83 | 74 |
Total with no related allowance recorded, Recorded Investment | 108 | 83 | 74 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 69 | 70 | 15 |
Total with no related allowance recorded, Income Recognized | | 4 | 47 |
Total with no related allowance recorded, Cash Basis Income Recognized | -1 | 3 | 47 |
Total with an allocated allowance recorded, Unpaid Principal Balance | | | 263 |
Total with an allocated allowance recorded, Recorded Investment | | | 263 |
Total Allowance for Loan Losses Allocated | | | 184 |
Total with an allocated allowance recorded, Average Recorded Investment | | 87 | 213 |
Total with an allocated allowance recorded, Income Recognized | | | 16 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | | 16 |
Owner Occupied [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | 1,411 | 1,097 |
Total with no related allowance recorded, Recorded Investment | | 1,411 | 1,097 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 353 | 1,159 | 1,017 |
Total with no related allowance recorded, Income Recognized | | 58 | 50 |
Total with no related allowance recorded, Cash Basis Income Recognized | | 64 | 48 |
Total with an allocated allowance recorded, Unpaid Principal Balance | 545 | 1,845 | 1,722 |
Total with an allocated allowance recorded, Recorded Investment | 545 | 1,845 | 1,722 |
Total Allowance for Loan Losses Allocated | 55 | 276 | 287 |
Total with an allocated allowance recorded, Average Recorded Investment | 734 | 1,862 | 1,105 |
Total with an allocated allowance recorded, Income Recognized | 64 | 129 | 149 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | 66 | 126 | 143 |
Non-Owner Occupied [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 3,188 | 3,582 | 1,992 |
Total with no related allowance recorded, Recorded Investment | 1,233 | 1,627 | 1,992 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 1,518 | 1,354 | 3,519 |
Total with no related allowance recorded, Income Recognized | 3 | | 766 |
Total with no related allowance recorded, Cash Basis Income Recognized | 3 | | 835 |
Total with an allocated allowance recorded, Unpaid Principal Balance | | | 2,132 |
Total with an allocated allowance recorded, Recorded Investment | | | 2,132 |
Total Allowance for Loan Losses Allocated | | | 30 |
Total with an allocated allowance recorded, Average Recorded Investment | 604 | 1,224 | 6,130 |
Total with an allocated allowance recorded, Income Recognized | | | 131 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | | 132 |
Other Real Estate Loans [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | 119 | 126 |
Total with no related allowance recorded, Recorded Investment | | 119 | 126 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 88 | 123 | 32 |
Total with no related allowance recorded, Income Recognized | | | 30 |
Total with no related allowance recorded, Cash Basis Income Recognized | | | 37 |
Total with an allocated allowance recorded, Unpaid Principal Balance | | | 2,204 |
Total with an allocated allowance recorded, Recorded Investment | | | 2,204 |
Total Allowance for Loan Losses Allocated | | | 70 |
Total with an allocated allowance recorded, Average Recorded Investment | | 1,100 | 2,217 |
Total with an allocated allowance recorded, Income Recognized | | | 143 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | | 143 |
Commercial and Industrial [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | | 345 |
Total with no related allowance recorded, Recorded Investment | | | 345 |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 28 | 1 | 125 |
Total with no related allowance recorded, Income Recognized | | | 26 |
Total with no related allowance recorded, Cash Basis Income Recognized | | | 25 |
Total with an allocated allowance recorded, Unpaid Principal Balance | | 176 | 37 |
Total with an allocated allowance recorded, Recorded Investment | | 176 | 37 |
Total Allowance for Loan Losses Allocated | | 176 | 12 |
Total with an allocated allowance recorded, Average Recorded Investment | 92 | 374 | 172 |
Total with an allocated allowance recorded, Income Recognized | | -35 | 1 |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | | 1 |
Consumer [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 4 | 1 | |
Total with no related allowance recorded, Recorded Investment | 4 | 1 | |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 3 | | 11 |
Total with no related allowance recorded, Income Recognized | | | |
Total with no related allowance recorded, Cash Basis Income Recognized | | | |
Total with an allocated allowance recorded, Unpaid Principal Balance | 3 | 11 | |
Total with an allocated allowance recorded, Recorded Investment | 3 | 11 | |
Total Allowance for Loan Losses Allocated | | | |
Total with an allocated allowance recorded, Average Recorded Investment | 9 | 7 | 62 |
Total with an allocated allowance recorded, Income Recognized | | 1 | |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | 1 | |
Other Loans [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | 6,652 | | |
Total with no related allowance recorded, Recorded Investment | 1,351 | | |
Total with no related allowance recorded, Allowance for Loan Losses Allocated | | | |
Total with no related allowance recorded, Average Recorded Investment | 676 | | 914 |
Total with no related allowance recorded, Income Recognized | | | |
Total with no related allowance recorded, Cash Basis Income Recognized | | | |
Total with an allocated allowance recorded, Unpaid Principal Balance | | 6,227 | 6,227 |
Total with an allocated allowance recorded, Recorded Investment | | 1,853 | 1,853 |
Total Allowance for Loan Losses Allocated | | 926 | 364 |
Total with an allocated allowance recorded, Average Recorded Investment | 926 | 1,853 | 3,775 |
Total with an allocated allowance recorded, Income Recognized | | | |
Total with an allocated allowance recorded, Cash Basis Income Recognized | | | |
Farmland [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Average Recorded Investment | | | 187 |
Agricultural [Member] | | | |
Financing Receivable, Impaired [Line Items] | | | |
Total with no related allowance recorded, Unpaid Principal Balance | | 1 | |
Total with no related allowance recorded, Recorded Investment | | 1 | |
Total with no related allowance recorded, Average Recorded Investment | | $93 | |