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Note 2 - Securities - Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Investment securities available for sale, amortized cost | $ 341,011 | $ 333,950
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 310,860 | 295,623
Collateralized Mortgage-Backed Securities [Member] |  |
Due within one year, amortized cost | 19,249 | 25,279
Due within one year, estimated fair value | 19,091 | 25,017
Due after one through five years, amortized cost | 4,264 | 16,622
Due after one through five years, estimated fair value | 4,226 | 16,029
Due after five through ten years, amortized cost | 8,141 | 8,874
Due after five through ten years, estimated fair value | 7,782 | 8,197
Due after ten years, amortized cost | 118,709 | 106,445
Due after ten years, estimated fair value | 105,336 | 90,097
Investment securities available for sale, amortized cost | 150,363 | 157,220
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 136,435 | 139,340
Investment Securities, Excluding Mortgage Backed Securities [Member] |  |
Due within one year, amortized cost | 1,000 | 300
Due within one year, estimated fair value | 815 | 300
Due after one through five years, amortized cost | 20,574 | 18,187
Due after one through five years, estimated fair value | 19,857 | 17,384
Due after five through ten years, amortized cost | 53,073 | 57,328
Due after five through ten years, estimated fair value | 48,893 | 50,768
Due after ten years, amortized cost | 116,001 | 100,915
Due after ten years, estimated fair value | 104,860 | 87,831
Investment securities available for sale, amortized cost | 190,648 | 176,730
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | $ 174,425 | $ 156,283

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