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Note 10 - Stock-based Compensation (Tables) | 12 Months Ended
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Dec. 31, 2024
Notes Tables |
Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] |
|  |  |  |  |  | Weighted |
|  |  |  |  |  | Average |
|  | Shares |  |  | Fair Value |
Nonvested at beginning of year |  |  | 355,890 |  |  | $ | 34.18 |
Vested |  |  | (115,762 | ) |  |  | 32.02 |
Forfeited |  |  | (11,482 | ) |  |  | 34.09 |
Nonvested at end of year |  |  | 228,646 |  |  | $ | 35.84 |
Corporate and Bank Board Members [Member] |
Notes Tables |
Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block] |
|  |  |  |  |  | Total Cost |  |
Grant Year |  | Shares Granted |  |  | (in thousands) |  | Covered Period
2021 |  |  | 10,489 |  |  | $ | 344 |  | June 1, 2021 - May 31, 2022
2022 |  |  | 11,166 |  |  |  | 359 |  | June 1, 2022 - May 31, 2023
2023 |  |  | 11,529 |  |  |  | 350 |  | June 1, 2023 - May 31, 2024
2024 |  |  | 11,316 |  |  |  | 423 |  | June 1, 2024 - May 31, 2025

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