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Disclosures about Fair Value of Assets and Liabilities - Quantitative Information about Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements (Detail) $ in Thousands | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Jun. 30, 2019 USD ($) | May 31, 2020 | Mar. 31, 2020 USD ($) | Dec. 31, 2019
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights | $ 853 |  | $ 821 |
Impaired loans (collateral-dependent) | 33 |  |  |
Foreclosed assets | $ 512 |  |  |
Minimum [Member] | Discount Rate [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input | 950 |  |  |
Minimum [Member] | Constant Prepayment Rate [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) | 8.3 |  |  |
Minimum [Member] | Marketability Discount [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input |  |  | 9.5 |
Minimum [Member] | Marketability Discount [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) | 1,110 |  | 1,200 |
Minimum [Member] | Comparability Adjustments [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Foreclosed assets | 780 |  | 5 | 0.05
Maximum [Member] | Discount Rate [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input | 1,150 |  |  |
Maximum [Member] | Constant Prepayment Rate [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) | 11.0 |  |  |
Maximum [Member] | Marketability Discount [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input |  |  | 11.5 |
Maximum [Member] | Marketability Discount [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) | (1,110) | 14.5 |  |
Maximum [Member] | Comparability Adjustments [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Foreclosed assets | (780) |  | 0.12 | 0.12
Weighted Average [Member] | Discount Rate [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input | (950) |  |  |
Weighted Average [Member] | Constant Prepayment Rate [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) | 9.0 |  |  |
Weighted Average [Member] | Marketability Discount [Member] | Discounted Cash Flow [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Mortgage servicing rights, measurement input |  |  | 9.5 |
Weighted Average [Member] | Marketability Discount [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Impaired loans (collateral-dependent) |  |  | 1,210 |
Weighted Average [Member] | Comparability Adjustments [Member] | Market Comparable Properties [Member] |  |  |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |  |  |
Foreclosed assets |  |  | 11 | 0.11

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