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ACQUISITIONS - Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jul. 12, 2019
Fair Value of Subordinated Notes Payable
Subordinated notes payable	$ 3,249	$ 3,277
Certain Loans Acquired During The Period
Merger and acquisition integration related (recoveries) expenses	$ 5,021	701	$ 4,933
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
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	$ 5,000	$ 700	$ 4,900
NuVantage Insurance Corp. \| 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