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v3.25.3

Note 2 - Securities (Details Textual) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2025 USD ($) | Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 643 | 843
Debt Securities, Available-for-Sale, Unrealized Loss Position | $ 537,381 | $ 680,417
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss | 41,007 | 63,807
Proceeds from Sale of Debt Securities, Available-for-Sale | 0 | 0
Debt Securities, Available-for-Sale, Amortized Cost | 891,228 | 793,422
Debt Securities, Available-for-Sale | 855,138 | 730,352
Bonds Issued or Guaranteed by Agencies of the U.S. Federal Government [Member] |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss | 34,400 |
Bonds Issued by State-based Municipalities [Member] |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss | 6,600 |
State of Michigan and All Its Political Subdivisions [Member] |  |
Debt Securities, Available-for-Sale, Amortized Cost | 229,000 | 219,000
Debt Securities, Available-for-Sale | 224,000 | 209,000
All Other States and Their Political Subdivisions [Member] |  |
Debt Securities, Available-for-Sale, Amortized Cost | 0 | 0
US Government Agency Debt Obligations and Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-Sale, Restricted | 251,000 | 122,000
US Government Agencies Debt Securities [Member] |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position | 370,987 | 475,113
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss | 29,573 | 47,226
Debt Securities, Available-for-Sale, Amortized Cost | 632,999 | 542,676
Debt Securities, Available-for-Sale | 606,782 | 495,581
Debt Securities, Available-for-Sale, Restricted | $ 12,500 | $ 11,700

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