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Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2019 | Dec. 31, 2018 | Jun. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Interest-bearing deposits maturing date | 90 days |  |
Collateral dependent impaired loans categorized as Level 3 | $ 2,176 | $ 2,054 | $ 1,452
Specific allocation for collateral dependent impaired loans | 235 | 31 | $ 132
Collateral Dependent [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Specific allocation for collateral dependent impaired loans | 50 | 31 |
Level 3 [Member] | Collateral Dependent [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Collateral dependent impaired loans categorized as Level 3 | $ 159 | $ 215 |

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