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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) | Mar. 31, 2023 | Dec. 31, 2022
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 91,866,000 | $ 193,930,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 7,604,000 | 17,438,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 468,191,000 | 379,216,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 64,923,000 | 65,843,000
Securities available for sale, continuous unrealized loss position | 560,057,000 | 573,146,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 72,527,000 | 83,281,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 14,000,000 | 53,019,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 755,000 | 5,713,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 382,220,000 | 335,725,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 57,025,000 | 59,379,000
Securities available for sale, continuous unrealized loss position | 396,220,000 | 388,744,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 57,780,000 | 65,092,000
Collateralized Mortgage-Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 29,016,000 | 31,127,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 5,508,000 | 6,068,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 1,742,000 | 12,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 88,000 | 0
Securities available for sale, continuous unrealized loss position | 30,758,000 | 31,139,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 5,596,000 | 6,068,000
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 43,446,000 | 97,252,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 940,000 | 4,516,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 67,822,000 | 32,870,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 5,791,000 | 4,542,000
Securities available for sale, continuous unrealized loss position | 111,268,000 | 130,122,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 6,731,000 | 9,058,000
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 5,404,000 | 12,532,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 401,000 | 1,141,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 16,407,000 | 10,609,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 2,019,000 | 1,922,000
Securities available for sale, continuous unrealized loss position | 21,811,000 | 23,141,000
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 2,420,000 | $ 3,063,000

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