LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands	Jun. 30, 2023		Mar. 31, 2023	Dec. 31, 2022		Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 1,893,906			$ 1,829,448
Allowance for credit losses	(20,172)	[1]	$ (20,075)	(19,659)	[1]	$ (17,485)	$ (19,928)	$ (21,025)
Loans, net	1,873,734			1,809,789
Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	124,942
Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	923,585
Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	85,283
Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	210,532
Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	10,674
Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	253,806			252,293
Allowance for credit losses	(4,121)		(4,053)	(3,373)		(3,564)	(3,485)	(3,591)
Commercial Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	1,048,527			996,913
Allowance for credit losses	(10,994)		(10,983)	(11,576)		(10,314)	(12,963)	(13,556)
Commercial Mortgages | Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	124,942			108,243
Commercial Mortgages | Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	923,585			888,670
Residential Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	285,084			285,672
Allowance for credit losses	(1,905)		(1,892)	(1,845)		(1,714)	(1,606)	(1,803)
Consumer Loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	306,489			294,570
Allowance for credit losses	(3,152)		$ (3,147)	(2,865)		$ (1,893)	$ (1,874)	$ (2,075)
Consumer Loans | Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	85,283			81,401
Consumer Loans | Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	210,532			202,124
Consumer Loans | Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	10,674			11,045
Commercial and industrial
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	253,501
Commercial and industrial | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	253,501			252,044
Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	305
Agricultural | Commercial and Agricultural
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 305			$ 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.