LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2023		Jun. 30, 2023	Dec. 31, 2022		Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 1,930,688			$ 1,829,448
Allowance for credit losses	(20,252)	[1]	$ (20,172)	(19,659)	[1]	$ (18,631)	$ (17,485)	$ (21,025)
Loans, net	1,910,436			1,809,789
Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	140,480
Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	946,053
Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	87,078
Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	211,046
Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	10,186
Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	254,484			252,293
Allowance for credit losses	(4,146)		(4,121)	(3,373)		(3,515)	(3,564)	(3,591)
Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	1,086,533			996,913
Allowance for credit losses	(11,025)		(10,994)	(11,576)		(10,986)	(10,314)	(13,556)
Commercial mortgages, other | Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	140,480			108,243
Commercial mortgages, other | Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	946,053			888,670
Residential Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	281,361			285,672
Allowance for credit losses	(1,868)		(1,905)	(1,845)		(1,796)	(1,714)	(1,803)
Consumer Loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	308,310			294,570
Allowance for credit losses	(3,213)		$ (3,152)	(2,865)		$ (2,334)	$ (1,893)	$ (2,075)
Consumer Loans | Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	87,078			81,401
Consumer Loans | Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	211,046			202,124
Consumer Loans | Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	10,186			11,045
Commercial & industrial
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	254,215
Commercial & industrial | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	254,215			252,044
Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	269
Agricultural | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 269			$ 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.