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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 2,729 | $ 193,930
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 14 | 17,438
Securities available for sale, continuous unrealized loss position, 12 months or more | 546,018 | 379,216
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 66,098 | 65,843
Securities available for sale, continuous unrealized loss position | 548,747 | 573,146
Securities available for sale, continuous unrealized loss position, unrealized loss | 66,112 | 83,281
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 0 | 53,019
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 0 | 5,713
Securities available for sale, continuous unrealized loss position, 12 months or more | 390,496 | 335,725
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 52,000 | 59,379
Securities available for sale, continuous unrealized loss position | 390,496 | 388,744
Securities available for sale, continuous unrealized loss position, unrealized loss | 52,000 | 65,092
Collateralized Mortgage-Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 114 | 31,127
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 0 | 6,068
Securities available for sale, continuous unrealized loss position, 12 months or more | 28,749 | 12
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 5,715 | 0
Securities available for sale, continuous unrealized loss position | 28,863 | 31,139
Securities available for sale, continuous unrealized loss position, unrealized loss | 5,715 | 6,068
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 1,109 | 97,252
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 6 | 4,516
Securities available for sale, continuous unrealized loss position, 12 months or more | 106,171 | 32,870
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 6,184 | 4,542
Securities available for sale, continuous unrealized loss position | 107,280 | 130,122
Securities available for sale, continuous unrealized loss position, unrealized loss | 6,190 | 9,058
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 1,506 | 12,532
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 8 | 1,141
Securities available for sale, continuous unrealized loss position, 12 months or more | 20,602 | 10,609
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 2,199 | 1,922
Securities available for sale, continuous unrealized loss position | 22,108 | 23,141
Securities available for sale, continuous unrealized loss position, unrealized loss | 2,207 | 3,063
Other Debt and Equity Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 0 | 0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 0 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more | 0 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 0 | 0
Securities available for sale, continuous unrealized loss position | 0 | 0
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 0 | $ 0

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