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Investment Securities - Narrative (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract] |  |  |
Securities transferred from available-for-sale to held-to-maturity | $ 0 | $ 0 | $ 27,422,000
Unrealized pre-tax loss from transfer of available-for-sale securities to held-to-maturity |  |  | 278,000
Amortization of net unrealized losses on securities transferred from available-for-sale to held-to-maturity | $ 524,000 | $ 445,000 | $ 516,000

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- References No definition available. + Details
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