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Note 14 - Subsequent Events (Details Textual) $ / shares in Units, $ in Millions |  |  | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | --- | ---
Jul. 22, 2025 USD ($) $ / shares | Jul. 17, 2025 $ / shares | Jun. 30, 2025 $ / shares | Jun. 30, 2024 $ / shares | Jun. 30, 2025 $ / shares | Jun. 30, 2024 $ / shares | Jul. 21, 2025 $ / shares
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share) |  |  | $ 0.37 | $ 0.35 | $ 0.74 | $ 0.7 |
Subsequent Event [Member] |  |  |  |  |  |  |
Share Price (in dollars per share) |  |  |  |  |  |  | $ 48.75
Subsequent Event [Member] | Eastern Michigan Financial Corporation [Member] |  |  |  |  |  |  |
Business Combination, Acquiree's Common Stock Conversion to Cash Ratio (in dollars per share) | $ 32.32 |  |  |  |  |  |
Business Combination, Acquiree's Common Stock Conversion to Acquire's Common Stock Ratio | 0.7116 |  |  |  |  |  |
Business Combination, Consideration Transferred | $ | $ 95.8 |  |  |  |  |  |
Subsequent Event [Member] | O 2025 Q3 Dividends [Member] |  |  |  |  |  |  |
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share) |  | $ 0.38 |  |  |  |  |
Dividends Payable, Date Declared |  | Jul. 17, 2025 |  |  |  |  |
Dividends Payable, Date to be Paid |  | Sep. 17, 2025 |  |  |  |  |
Dividends Payable, Date of Record |  | Sep. 05, 2025 |  |  |  |  |

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