| **Loans and Allowance - Summary of Troubled Debt Restructurings by Modification (Detail) (USD $)In Thousands, unless otherwise specified** | Dec. 31, 2013 | Dec. 31, 2012 |
|--------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | $ 4,519       | $ 11,955      |
| Troubled Debt Restructurings, Term Modifications                                                                                           |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 1,823         | 7,452         |
| Troubled Debt Restructurings, Rate Modifications                                                                                           |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 275           | 1,290         |
| Troubled Debt Restructurings, Rate and Term Modifications                                                                                  |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 2,421         | 3,213         |
| Commercial and industrial loans                                                                                                            |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 267           | 1,288         |
| Commercial and industrial loans | Troubled Debt Restructurings, Term Modifications                                                         |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 207           | 259           |
| Commercial and industrial loans | Troubled Debt Restructurings, Rate and Term Modifications                                                |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 60            | 1,029         |
| Construction                                                                                                                               |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               |          | 625           |
| Construction | Troubled Debt Restructurings, Rate and Term Modifications                                                                   |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               |          | 625           |
| Commercial and farmland                                                                                                                    |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 3,373         | 7,952         |
| Commercial and farmland | Troubled Debt Restructurings, Term Modifications                                                                 |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 1,388         | 6,668         |
| Commercial and farmland | Troubled Debt Restructurings, Rate Modifications                                                                 |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               |          | 903           |
| Commercial and farmland | Troubled Debt Restructurings, Rate and Term Modifications                                                        |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 1,985         | 381           |
| Residential                                                                                                                                |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 755           | 1,900         |
| Residential | Troubled Debt Restructurings, Term Modifications                                                                             |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 167           | 525           |
| Residential | Troubled Debt Restructurings, Rate Modifications                                                                             |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 237           | 380           |
| Residential | Troubled Debt Restructurings, Rate and Term Modifications                                                                    |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 351           | 995           |
| Consumer                                                                                                                                   |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 124           | 190           |
| Consumer | Troubled Debt Restructurings, Term Modifications                                                                                |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 61            |          |
| Consumer | Troubled Debt Restructurings, Rate Modifications                                                                                |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | 38            | 7             |
| Consumer | Troubled Debt Restructurings, Rate and Term Modifications                                                                       |          |          |
| **Financing Receivable, Modifications [Line Items]**                                                                                       |          |          |
| Modification                                                                                                                               | $ 25          | $ 183         |

| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancingReceivableModificationsLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554
+ Details**Name:**us-gaap_FinancingReceivableModificationsRecordedInvestment**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |