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ACQUISITIONS - Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Jul. 12, 2019 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Fair Value of Subordinated Notes Payable [Abstract] |  |  |  |
Subordinated notes payable |  | $ 3,277 | $ 3,303 |
Summary of loans acquired [Abstract] |  |  |  |
Merger and acquisition integration related (recoveries) expenses |  | $ 701 | 4,933 | $ 8,608
Kinderhook Bank Corp [Member] | Core deposit intangibles |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  | 8 years |  |
Kinderhook Bank Corp [Member] | Other intangibles |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  | 8 years |  |
Kinderhook Bank Corp [Member] | Subordinated Notes Maturing in February 2028 [Member] |  |  |  |
Fair Value of Subordinated Notes Payable [Abstract] |  |  |  |
Subordinated notes payable | $ 3,000 |  |  |
Fixed interest rate percentage | 6.00% |  |  |
Maturity date | Feb. 29, 2028 |  |  |
Kinderhook Bank Corp [Member] | Subordinated Notes Maturing in November 2025 [Member] |  |  |  |
Fair Value of Subordinated Notes Payable [Abstract] |  |  |  |
Subordinated notes payable | $ 10,000 |  |  |
Fixed interest rate percentage | 6.375% |  |  |
Maturity date | Nov. 30, 2025 |  |  |
Steuben Trust Corporation [Member] |  |  |  |
Summary of loans acquired [Abstract] |  |  |  |
Merger and acquisition integration related (recoveries) expenses |  | $ 700 | $ 4,900 | $ 8,600
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  | 15 years |  |
Thomas Gregory Associates [Member] |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  | 13 years |  |

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460 + Details
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 1B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)(a)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
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