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AFS Securities (Amortized cost and fair value of AFS securities by contractual maturity) (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
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Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | $ 15,461 |
Maturing, After One Year But Within Five Years | 259,300 |
Maturing, After Five Years But Within Ten Years | 28,153 |
Maturing, After Ten Years | 31,291 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 225,769 |
Debt Securities, Available-for-sale, Amortized Cost | 559,974 | $ 625,605
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 15,907 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 242,998 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 26,400 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value | 29,322 |
Available-for-sale Securities, With Variable Monthly Payments Or Without Single Maturity Date, Fair Value | 213,521 |
Debt Securities, Available-for-sale | 528,148 | 580,481
US Treasury Securities |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 0 |
Maturing, After One Year But Within Five Years | 231,218 |
Maturing, After Five Years But Within Ten Years | 0 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 231,218 | 231,622
Debt Securities, Available-for-sale | 214,801 | 208,701
States and political subdivisions [Member] |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 15,461 |
Maturing, After One Year But Within Five Years | 28,082 |
Maturing, After Five Years But Within Ten Years | 20,003 |
Maturing, After Ten Years | 31,291 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 94,837 | 122,023
Debt Securities, Available-for-sale | 92,876 | 117,512
Auction rate money market preferred [Member] |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 0 |
Maturing, After One Year But Within Five Years | 0 |
Maturing, After Five Years But Within Ten Years | 0 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 3,200 |
Debt Securities, Available-for-sale, Amortized Cost | 3,200 | 3,200
Debt Securities, Available-for-sale | 2,931 | 2,342
Mortgage-backed securities [Member] |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 0 |
Maturing, After One Year But Within Five Years | 0 |
Maturing, After Five Years But Within Ten Years | 0 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 35,321 |
Debt Securities, Available-for-sale, Amortized Cost | 35,321 | 42,309
Debt Securities, Available-for-sale | 32,815 | 39,070
Collateralized mortgage obligations [Member] |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 0 |
Maturing, After One Year But Within Five Years | 0 |
Maturing, After Five Years But Within Ten Years | 0 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 187,248 |
Debt Securities, Available-for-sale, Amortized Cost | 187,248 | 218,301
Debt Securities, Available-for-sale | 177,775 | 205,728
Corporate Debt Securities |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 0 |
Maturing, After One Year But Within Five Years | 0 |
Maturing, After Five Years But Within Ten Years | 8,150 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 8,150 | 8,150
Debt Securities, Available-for-sale | $ 6,950 | $ 7,128

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