LOANS AND ALLOWANCE FOR CREDIT LOSSES - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) loan		Dec. 31, 2022 USD ($)		Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable on loans	$ 7,800,000		$ 6,500,000
Residential mortgages held for sale	0		0
Allowance for credit losses	22,517,000	[1]	19,659,000	[1]	$ 21,025,000
Loans individually analyzed	$ 8,035,000		7,482,000
Number of days past due after which a retail loan is rated	90 days
Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 267,000
Loans individually analyzed	6,347,000
Residential Mortgages and Home Equity Loans | Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial instruments, owned, at fair value	254,600,000		254,400,000
Commercial and Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	5,055,000		3,373,000		$ 3,591,000
Loans individually analyzed	$ 2,067,000		$ 2,112,000
Commercial and Agricultural | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of contracts modified | loan	1
Allowance for credit losses	$ 900,000

[1] Effective January 1, 2023, the allowance calculation is based upon Current Expected Credit loss methodology. Prior to January 1, 2023, the allowance calculation was based upon incurred loss methodology. Refer to Note 1 for further discussion.