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Note 13 - Fair Value Measurement - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Jun. 30, 2024 | Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | --- | --- | --- | --- | ---
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | $ 310,860 |  | $ 295,623 |  |  |
Sold loan servicing rights | 3,584 |  | 3,793 |  |  |
Fair Value, Recurring [Member] |  |  |  |  |  |
Sold loan servicing rights | 3,584 |  | 3,793 |  |  |
Equity and partnership investments | 14,412 |  | 13,183 |  |  |
Total assets measured at fair value | 328,856 |  | 312,599 |  |  |
Fair Value, Recurring [Member] | Derivative Financial Instruments, Assets [Member] |  |  |  |  |  |
Interest rate swap derivative | 2,749 |  |  |  |  |
Fair Value, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |
Interest rate swap derivative |  |  | 1,002 |  |  |
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Sold loan servicing rights | 0 |  | 0 |  |  |
Equity and partnership investments | 0 |  | 0 |  |  |
Total assets measured at fair value | 6,999 |  | 7,001 |  |  |
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Assets [Member] |  |  |  |  |  |
Interest rate swap derivative | 0 |  |  |  |  |
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |
Interest rate swap derivative |  |  | 0 |  |  |
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Sold loan servicing rights | 0 |  | 0 |  |  |
Equity and partnership investments | 1,762 |  | 0 |  |  |
Total assets measured at fair value | 288,528 |  | 261,153 |  |  |
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Assets [Member] |  |  |  |  |  |
Interest rate swap derivative | 2,749 |  |  |  |  |
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |
Interest rate swap derivative |  |  | 1,002 |  |  |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Sold loan servicing rights | 3,584 | $ 3,740 | 3,793 | $ 3,729 | $ 3,825 | $ 3,887
Equity and partnership investments | 12,650 |  | 13,183 |  |  |
Total assets measured at fair value | 33,329 |  | 44,445 |  |  |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Assets [Member] |  |  |  |  |  |
Interest rate swap derivative | 0 |  |  |  |  |
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |  |
Interest rate swap derivative |  |  | 0 |  |  |
US States and Political Subdivisions Debt Securities [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 81,363 |  | 87,761 |  |  |
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 81,363 |  | 87,761 |  |  |
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 5,054 |  | 5,118 |  |  |
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 76,309 |  | 82,643 |  |  |
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
US Government Agencies Debt Securities [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 13,296 |  | 11,782 |  |  |
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 13,296 |  | 11,782 |  |  |
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 13,296 |  | 11,782 |  |  |
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Corporate Issued Asset-backed Securities [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 16,391 |  | 5,286 |  |  |
Corporate Issued Asset-backed Securities [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 16,391 |  | 5,286 |  |  |
Corporate Issued Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Corporate Issued Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 16,391 |  | 5,286 |  |  |
Corporate Issued Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Corporate Debt Securities [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 54,058 |  | 51,454 |  |  |
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 54,058 |  | 51,454 |  |  |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 1,945 |  | 1,883 |  |  |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 52,113 |  | 49,571 |  |  |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
US Small Business Administration Securities [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 9,317 |  |  |  |  |
US Small Business Administration Securities [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 9,317 |  |  |  |  |
US Small Business Administration Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  |  |  |  |
US Small Business Administration Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 9,317 |  |  |  |  |
US Small Business Administration Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  |  |  |  |
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 78,549 |  | 63,247 |  |  |
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 78,549 |  | 63,247 |  |  |
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 78,549 |  | 63,247 |  |  |
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Mortgage-Backed Securities, Issued by Private Enterprises [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 57,886 |  | 76,093 |  |  |
Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 57,886 |  | 76,093 |  |  |
Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 0 |  | 0 |  |  |
Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | 40,791 |  | 48,624 |  |  |
Mortgage-Backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |  |  |  |  |
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively) | $ 17,095 |  | $ 27,469 |  |  |

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