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Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) | Mar. 31, 2022 | Dec. 31, 2021
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Securities available for sale, continuous unrealized loss position, less than 12 months | $ 293,910,000 | $ 351,062,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 18,152,000 | 6,455,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 240,819,000 | 110,491,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 22,994,000 | 3,503,000
Securities available for sale, continuous unrealized loss position | 534,729,000 | 461,553,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 41,146,000 | 9,958,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 190,990,000 | 274,287,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 11,971,000 | 5,274,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 215,783,000 | 110,053,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 20,025,000 | 3,495,000
Securities available for sale, continuous unrealized loss position | 406,773,000 | 384,340,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 31,996,000 | 8,769,000
Collateralized Mortgage-Backed Securities [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 26,110,000 | 23,184,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 1,783,000 | 652,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 6,594,000 | 24,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 809,000 | 0
Securities available for sale, continuous unrealized loss position | 32,704,000 | 23,208,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 2,592,000 | 652,000
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 63,139,000 | 40,748,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 3,399,000 | 392,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 12,600,000 | 0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 1,386,000 | 0
Securities available for sale, continuous unrealized loss position | 75,739,000 | 40,748,000
Securities available for sale, continuous unrealized loss position, unrealized loss | 4,785,000 | 392,000
Municipal Revenue Bonds [Member] |  |
Securities available for sale, continuous unrealized loss position, less than 12 months | 13,671,000 | 12,843,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss | 999,000 | 137,000
Securities available for sale, continuous unrealized loss position, 12 months or more | 5,842,000 | 414,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss | 774,000 | 8,000
Securities available for sale, continuous unrealized loss position | 19,513,000 | 13,257,000
Securities available for sale, continuous unrealized loss position, unrealized loss | $ 1,773,000 | $ 145,000

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