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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) | Sep. 30, 2023 | Dec. 31, 2022
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 68,756,000 | $ 193,930,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 12,717,000 | 17,438,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 516,942,000 | 379,216,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 80,482,000 | 65,843,000
Securities available for sale, continuous unrealized loss position | 585,698,000 | 573,146,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 93,199,000 | 83,281,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 2,679,000 | 53,019,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 1,124,000 | 5,713,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 381,400,000 | 335,725,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 67,127,000 | 59,379,000
Securities available for sale, continuous unrealized loss position | 384,079,000 | 388,744,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 68,251,000 | 65,092,000
Collateralized Mortgage-Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 26,231,000 | 31,127,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 7,558,000 | 6,068,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 1,604,000 | 12,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 127,000 | 0
Securities available for sale, continuous unrealized loss position | 27,835,000 | 31,139,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 7,685,000 | 6,068,000
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 33,136,000 | 97,252,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 2,992,000 | 4,516,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 115,872,000 | 32,870,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 10,538,000 | 4,542,000
Securities available for sale, continuous unrealized loss position | 149,008,000 | 130,122,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 13,530,000 | 9,058,000
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 6,710,000 | 12,532,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 1,043,000 | 1,141,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 18,066,000 | 10,609,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 2,690,000 | 1,922,000
Securities available for sale, continuous unrealized loss position | 24,776,000 | 23,141,000
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 3,733,000 | $ 3,063,000

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