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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) | Sep. 30, 2021 | Dec. 31, 2020
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 341,046,000 | $ 119,073,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 4,954,000 | 899,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 49,160,000 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 1,002,000 | 0
Securities available for sale, continuous unrealized loss position | 390,206,000 | 119,073,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 5,956,000 | 899,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 274,190,000 | 118,650,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 3,974,000 | 897,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 48,317,000 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 980,000 | 0
Securities available for sale, continuous unrealized loss position | 322,507,000 | 118,650,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 4,954,000 | 897,000
Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 23,578,000 | 0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 544,000 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more | 23,000 | 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 | 23,601,000 | 0
Securities available for sale, continuous unrealized loss position, unrealized loss | 544,000 | 0
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 32,180,000 | 0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 278,000 | 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 | 32,180,000 | 0
Securities available for sale, continuous unrealized loss position, unrealized loss | 278,000 | 0
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 11,098,000 | 423,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 158,000 | 2,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 820,000 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 22,000 | 0
Securities available for sale, continuous unrealized loss position | 11,918,000 | 423,000
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 180,000 | $ 2,000

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