Off-Balance Sheet Financial Instruments (Detail) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
| Commitments to extend credit | $ 260,416 | $ 235,302 |
| Standby letters of credit and financial guarantees | 7,981 | 7,765 |
| Total off-balance sheet risk | 268,397 | 243,067 |
| Reserve for unfunded commitments | $ 326 | $ 326 |