Commitments and Contingencies - Summary of Commitments to Extend Credit (Detail) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Loan commitments [Member] | ||
| Loss Contingencies [Line Items] | ||
| Commitments to extend credit | $ 162,212 | $ 149,561 |
| Standby letters of credit [Member] | ||
| Loss Contingencies [Line Items] | ||
| Commitments to extend credit | $ 1,033 | $ 382 |