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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) | Jun. 30, 2023 | Dec. 31, 2022
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 78,091,000 | $ 193,930,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 8,985,000 | 17,438,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 500,297,000 | 379,216,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 69,509,000 | 65,843,000
Securities available for sale, continuous unrealized loss position | 578,388,000 | 573,146,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 78,494,000 | 83,281,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 2,862,000 | 53,019,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 940,000 | 5,713,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 390,232,000 | 335,725,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 60,130,000 | 59,379,000
Securities available for sale, continuous unrealized loss position | 393,094,000 | 388,744,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 61,070,000 | 65,092,000
Collateralized Mortgage-Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 27,997,000 | 31,127,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 5,759,000 | 6,068,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 1,811,000 | 12,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 105,000 | 0
Securities available for sale, continuous unrealized loss position | 29,808,000 | 31,139,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 5,864,000 | 6,068,000
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 39,970,000 | 97,252,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 1,476,000 | 4,516,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 92,626,000 | 32,870,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 7,263,000 | 4,542,000
Securities available for sale, continuous unrealized loss position | 132,596,000 | 130,122,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 8,739,000 | 9,058,000
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 7,262,000 | 12,532,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 810,000 | 1,141,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 15,628,000 | 10,609,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 2,011,000 | 1,922,000
Securities available for sale, continuous unrealized loss position | 22,890,000 | 23,141,000
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 2,821,000 | $ 3,063,000

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