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AFS Securities (Amortized cost and fair value of AFS securities by contractual maturity) (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
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Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | $ 25,095 |
Maturing, After One Year But Within Five Years | 248,760 |
Maturing, After Five Years But Within Ten Years | 28,063 |
Maturing, After Ten Years | 30,915 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 219,504 |
Amortized Cost | 552,337 | $ 559,974
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less, Fair value | 25,158 |
Maturing, After One Year But Within Five Years, Fair value | 232,115 |
Maturing, After Five Years But Within Ten Years, Fair value | 26,197 |
Maturing, After Ten Years, Fair value | 28,227 |
Securities With Variable Monthly Payments or Noncontractual Maturities, Fair value | 205,888 |
Total, Fair value | 517,585 | 528,148
US Treasury Securities |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 9,990 |
Maturing, After One Year But Within Five Years | 221,124 |
Maturing, After Five Years But Within Ten Years | 0 |
Maturing, After Ten Years | 0 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 0 |
Amortized Cost | 231,114 | 231,218
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | 214,226 | 214,801
States and political subdivisions [Member] |  |
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] |  |
Maturing, Due in One Year or Less | 15,105 |
Maturing, After One Year But Within Five Years | 27,636 |
Maturing, After Five Years But Within Ten Years | 19,913 |
Maturing, After Ten Years | 30,915 |
Securities With Variable Monthly Payments or Noncontractual Maturities | 0 |
Amortized Cost | 93,569 | 94,837
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | 90,470 | 92,876
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 |
Amortized Cost | 3,200 | 3,200
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | 3,013 | 2,931
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 | 33,762 |
Amortized Cost | 33,762 | 35,321
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | 31,044 | 32,815
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 | 182,542 |
Amortized Cost | 182,542 | 187,248
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | 171,831 | 177,775
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 |
Amortized Cost | 8,150 | 8,150
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] |  |
Total, Fair value | $ 7,001 | $ 6,950

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