LOANS AND ALLOWANCE FOR LOAN LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands	Mar. 31, 2023		Dec. 31, 2022		Mar. 31, 2022	Dec. 31, 2021
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 1,873,701		$ 1,829,448
Allowance for credit losses	(20,075)	[1]	(19,659)	[1]	$ (19,928)	$ (21,025)
Loans, net	1,853,626		1,809,789
Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	118,660
Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	917,637
Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	84,537
Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	211,270
Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	11,146
Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	244,507		252,293
Allowance for credit losses	(4,053)		(3,373)		(3,483)	(3,591)
Commercial Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	1,036,297		996,913
Allowance for credit losses	(10,983)		(11,576)		(12,964)	(13,556)
Commercial Mortgages | Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	118,660		108,243
Commercial Mortgages | Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	917,637		888,670
Residential Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	285,944		285,672
Allowance for credit losses	(1,892)		(1,845)		(1,606)	(1,803)
Consumer Loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	306,953		294,570
Allowance for credit losses	(3,147)		(2,865)		$ (1,875)	$ (2,075)
Consumer Loans | Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	84,537		81,401
Consumer Loans | Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	211,270		202,124
Consumer Loans | Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	11,146		11,045
Commercial and industrial
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	244,174
Commercial and industrial | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	244,174		252,044
Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	333
Agricultural | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 333		$ 249

[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.