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Fair Values of Financial Instruments - Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements Other Than Goodwill (Details) - Significant Unobservable Inputs (Level 3) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Discounted cash flow | State and municipal securities |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 2,444 | $ 2,858
Discounted cash flow | State and municipal securities | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Maturity Call Date | 1 month | 1 month
US Muni BQ curve | A- | A-
Discounted cash flow | State and municipal securities | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Maturity Call Date | 15 years | 15 years
US Muni BQ curve | BBB- | BBB-
Discounted cash flow | State and municipal securities | Discount rate | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 0.015 | 0.02
Discounted cash flow | State and municipal securities | Discount rate | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 0.04 | 0.05
Discounted cash flow | State and municipal securities | Weighted-average coupon | Weighted Average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 0.0388 | 0.04
Discounted cash flow | Corporate obligations and U.S. Government-sponsored mortgage backed securities |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 35 | $ 35
Discounted cash flow | Corporate obligations and U.S. Government-sponsored mortgage backed securities | Weighted-average coupon | Weighted Average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 0 | 0
Discounted cash flow | Corporate obligations and U.S. Government-sponsored mortgage backed securities | Premium for illiquidity |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 0.02 | 0.02
Collateral based measurements | Impaired loans (collateral dependent) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 37,250 | $ 5,653
Collateral based measurements | Impaired loans (collateral dependent) | Discount to reflect current market conditions and ultimate collectability | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount to reflect current market conditions and ultimate collectability | 0 | 0
Collateral based measurements | Impaired loans (collateral dependent) | Discount to reflect current market conditions and ultimate collectability | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount to reflect current market conditions and ultimate collectability | 0.10 | 0.10
Collateral based measurements | Impaired loans (collateral dependent) | Discount to reflect current market conditions and ultimate collectability | Weighted Average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount to reflect current market conditions and ultimate collectability | 0.06 | 0.01
Appraisals | Other real estate owned |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 544 | $ 194
Appraisals | Other real estate owned | Discount to reflect current market conditions | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Other real estate owned | 0 | 0
Appraisals | Other real estate owned | Discount to reflect current market conditions | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Other real estate owned | 0.30 | 0.37
Appraisals | Other real estate owned | Discount to reflect current market conditions | Weighted Average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Other real estate owned | 0.26 | 0.37

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