ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCD loans allowance for credit losses at acquisition			$ 26,103
Interest income on impaired loans	$ 300	$ 200	600	$ 600
Loan workout and other credit costs	(1,001)	(196)	(1,103)	(764)
Troubled debt restructuring related reserves	300		$ 300		$ 200
Usual sustained repayment performance period			6 months
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCD loans allowance for credit losses at acquisition			$ 61
Number of loans in the process of foreclosure | loan			37		28
Total loans outstanding			$ 5,200		$ 2,500
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans in the process of foreclosure | loan			12		9
Total loans outstanding			$ 3,300		$ 3,200
Residential and Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan workout and other credit costs	$ 300	$ (600)	$ (500)	$ (1,400)
Impairment loans, charge off period			90 days
Bryn Mawr Bank Corporation Acquisition
Accounts, Notes, Loans and Financing Receivable [Line Items]
Initial allowance on acquired PCD loans			$ 49,600
Loans purchased with no credit deterioration			23,500
PCD loans allowance for credit losses at acquisition			$ 26,100