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Note 3 - Securities (Tables) | 12 Months Ended
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Dec. 31, 2020
Notes Tables |
Available-for-sale Securities [Table Text Block] |
|  | December 31, 2020 |
Available for sale: |  | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |
U.S. Government agencies and corporations |  | $ | 86,859 |  |  | $ | 4,477 |  |  | $ | 173 |  |  | $ | 91,163 |
States and political subdivisions |  |  | 196,435 |  |  |  | 7,778 |  |  |  | 252 |  |  |  | 203,961 |
Mortgage-backed securities |  |  | 244,780 |  |  |  | 4,473 |  |  |  | 78 |  |  |  | 249,175 |
Corporate debt securities |  |  | 2,001 |  |  |  | 442 |  |  |  | - |  |  |  | 2,443 |
Total securities available for sale |  | $ | 530,075 |  |  | $ | 17,170 |  |  | $ | 503 |  |  | $ | 546,742 |
|  | December 31, 2019 |
Available for sale: |  | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |
U.S. Government agencies and corporations |  | $ | 119,903 |  |  | $ | 1,995 |  |  | $ | 775 |  |  | $ | 121,123 |
States and political subdivisions |  |  | 88,092 |  |  |  | 791 |  |  |  | 644 |  |  |  | 88,239 |
Mortgage-backed securities |  |  | 223,173 |  |  |  | 45 |  |  |  | 1,435 |  |  |  | 221,783 |
Corporate debt securities |  |  | 3,998 |  |  |  | 120 |  |  |  | - |  |  |  | 4,118 |
Total securities available for sale |  | $ | 435,166 |  |  | $ | 2,951 |  |  | $ | 2,854 |  |  | $ | 435,263 |
Investments Classified by Contractual Maturity Date [Table Text Block] |
|  | December 31, 20 20 |
Available for sale: |  | Amortized Cost |  |  | Fair Value |
Due in one year or less |  | $ | 4,002 |  |  | $ | 4,048 |
Due after one year through five years |  |  | 5,605 |  |  |  | 5,787 |
Due after five years through ten years |  |  | 141,804 |  |  |  | 146,716 |
Due after ten years |  |  | 378,664 |  |  |  | 390,191 |
Total securities available for sale |  | $ | 530,075 |  |  | $ | 546,742 |
Schedule of Temporary Impairment Losses, Investments [Table Text Block] |
|  | December 31, 2020 |
|  | Less Than 12 Months |  |  | 12 Months or More |
|  | Fair Value |  |  | Unrealized Loss |  |  | Fair Value |  |  | Unrealized Loss |
U.S. Government agencies and corporations |  | $ | 28,798 |  |  | $ | 173 |  |  | $ | - |  |  | $ | - |
State and political subdivisions |  |  | 32,353 |  |  |  | 249 |  |  |  | 635 |  |  |  | 3 |
Mortgage-backed securities |  |  | 8,816 |  |  |  | 76 |  |  |  | 4,060 |  |  |  | 2 |
Total temporarily impaired securities |  | $ | 69,967 |  |  | $ | 498 |  |  | $ | 4,695 |  |  | $ | 5 |
|  | December 31, 2019 |
|  | Less Than 12 Months |  |  | 12 Months or More |
|  | Fair Value |  |  | Unrealized Loss |  |  | Fair Value |  |  | Unrealized Loss |
U.S. Government agencies and corporations |  | $ | 53,244 |  |  | $ | 738 |  |  | $ | 38,962 |  |  | $ | 37 |
State and political subdivisions |  |  | 35,934 |  |  |  | 596 |  |  |  | 591 |  |  |  | 48 |
Mortgage-backed securities |  |  | 181,279 |  |  |  | 1,435 |  |  |  | - |  |  |  | - |
Total temporarily impaired securities |  | $ | 270,457 |  |  | $ | 2,769 |  |  | $ | 39,553 |  |  | $ | 85 |
Schedule of Realized Gain (Loss) on Called Securities [Table Text Block] |
|  | For the year ended December 31, 2020 |
|  | Proceeds |  |  | Book Value |  |  | Gross Gain |  |  | Gross Loss |  |  | Net Gain |
Available for sale |  | $ | 126,840 |  |  | $ | 126,732 |  |  | $ | 110 |  |  | $ | 2 |  |  | $ | 108 |
|  | For the year ended December 31, 201 9 |
|  | Proceeds |  |  | Book Value |  |  | Gross Gain |  |  | Gross Loss |  |  | Net Gain |
Available for sale |  | $ | 348,032 |  |  | $ | 347,466 |  |  | $ | 1,157 |  |  | $ | 591 |  |  | $ | 566 |
|  | For the year ended December 31, 201 8 |
|  | Proceeds |  |  | Book Value |  |  | Gross Gain |  |  | Gross Loss |  |  | Net Gain |
Available for sale |  | $ | 17,287 |  |  | $ | 17,270 |  |  | $ | 17 |  |  | $ | - |  |  | $ | 17 |
Held to maturity |  |  | 6,430 |  |  |  | 6,430 |  |  |  | - |  |  |  | - |  |  |  | - |

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