ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($) loan	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income on impaired loans	$ 200	$ 200
Loan workout and other credit costs	328	1,120
Troubled debt restructuring related reserves	$ 100		$ 200
Usual sustained repayment performance period	6 months
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans in the process of foreclosure | loan	22		28
Total loans outstanding	$ 2,200		$ 2,500
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans in the process of foreclosure | loan	16		9
Total loans outstanding	$ 4,300		$ 3,200
Residential and Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan workout and other credit costs	$ 300	$ 500
Impairment loans, charge off period	90 days