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ACQUISITIONS - Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Jul. 12, 2019
Fair Value of Subordinated Notes Payable [Abstract] |  |  |  |
Subordinated notes payable | $ 0 | $ 3,249 |  |
Certain Loans Acquired During The Period |  |  |  |
Merger and acquisition integration related (recoveries) expenses | $ 63 | 5,021 | $ 701 |
Kinderhook Bank Corp. | Core deposit intangibles |  |  |  |
Identifiable Intangible Assets |  |  |  |
Estimated useful life | 10 years |  |  |
Kinderhook Bank Corp. | Subordinated Notes |  |  |  |
Fair Value of Subordinated Notes Payable [Abstract] |  |  |  |
Subordinated notes payable |  |  |  | $ 17,600
Fixed interest rate percentage |  |  |  | 2.48%
Steuben Trust Corporation |  |  |  |
Certain Loans Acquired During The Period |  |  |  |
Merger and acquisition integration related (recoveries) expenses | $ 100 | $ 5,000 | $ 700 |
NuVantage | Core deposit intangibles |  |  |  |
Identifiable Intangible Assets |  |  |  |
Estimated useful life | 8 years |  |  |
Fringe Benefits Design of Minnesota, Inc |  |  |  |
Identifiable Intangible Assets |  |  |  |
Estimated useful life | 15 years |  |  |
Thomas Gregory Associates Insurance Brokers, Inc. |  |  |  |
Identifiable Intangible Assets |  |  |  |
Estimated useful life | 13 years |  |  |

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