LOANS AND ALLOWANCE FOR LOAN LOSSES - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) numberOfBank loan property category	Dec. 31, 2019 USD ($) loan loanRelationship borrower property
Activity in the allowance for loan losses:
Number of additional collateralized loans in the process of foreclosure | numberOfBank	5
Investment in loans in the process of foreclosure	$ 200,000
Number foreclosed properties held | property	32
Number of points in internal risk rating system | category	9
Number of categories in internal risk rating system considered as not criticized | category	6
Commercial relationship credit review threshold amount	$ 1,000,000.0
Past due period before loans placed in non-accrual status	90 days
Recent loan payment history before removal from non-accrual status	6 months
Residential
Activity in the allowance for loan losses:
Number foreclosed properties held | property		11
Foreclosed properties held	$ 2,600,000	$ 600,000
Increase (decrease) in impaired loans (percentage)	56.60%	40.90%
Residential | Commercial Loan Relationship One
Activity in the allowance for loan losses:
Foreclosed properties held		$ 300,000
Residential | Commercial Loan Relationship Two
Activity in the allowance for loan losses:
Foreclosed properties held		200,000
Residential | Commercial Loan Relationship Three
Activity in the allowance for loan losses:
Foreclosed properties held		$ 100,000
Number of borrowers | borrower		2
Consumer
Activity in the allowance for loan losses:
Number of additional collateralized loans in the process of foreclosure | loan	11	7
Investment in loans in the process of foreclosure	$ 1,100,000	$ 600,000
Related allowance	$ 0	$ 0
Commercial
Activity in the allowance for loan losses:
Number of loan relationships causing increase in impaired loans | loanRelationship		2