LOANS AND LEASES - Restructured Loans (Details) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($) loans	Sep. 30, 2020 USD ($) loans	Jun. 30, 2021 loans	Sep. 30, 2021 USD ($) loans d	Sep. 30, 2020 USD ($) loans	Dec. 31, 2020 USD ($) loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				30	39
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 23,112	$ 17,033
Financing Receivable, Troubled Debt Restructuring, Postmodification				15,901	16,924
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	$ 100	$ 100		$ 100	100
Number of Restructured Loans | loans	152			152		155
Total restructured loans	$ 31,800			$ 31,800		$ 21,800
Restructured loans on accrual status	11,400			11,400		7,100
Restructured Loans, Nonaccrual Status	20,300			20,300		14,700
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	300			300		300
Allowance for loan and lease losses lncluded in reserves for restructured loans	6,300			6,300		8,800
Accruing TDRs performing in accordance with restructured terms for more than one year	5,200			$ 5,200		5,000
Restructured Loans, Portion Determined to be Uncollectible	$ 600	$ 600			$ 1,700
Restructured loans performance threshold (days) | d				90
Financing Receivable Modifications, Contracts, Number | loans	3	7
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 6,980	$ 1,709
Financing Receivable Modifications, Post Modification Investment Recorded	$ 903	$ 1,690
Commercial segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				5	8
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 4,967	$ 14,984
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 4,831	$ 14,984
Financing Receivable Modifications, Contracts, Number | loans	0	1
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 0	$ 1,480
Financing Receivable Modifications, Post Modification Investment Recorded	$ 0	$ 1,480
Construction real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				0	0
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 0	$ 0
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 0	$ 0
Financing Receivable Modifications, Contracts, Number | loans	0	0
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 0	$ 0
Financing Receivable Modifications, Post Modification Investment Recorded	$ 0	$ 0
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				8	0
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 16,850	$ 0
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 9,807	$ 0
Financing Receivable Modifications, Contracts, Number | loans	1	0
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 6,835	$ 0
Financing Receivable Modifications, Post Modification Investment Recorded	$ 761	$ 0
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				14	20
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 1,265	$ 1,677
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 1,233	$ 1,581
Financing Receivable Modifications, Contracts, Number | loans	1	2
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 145	$ 109
Financing Receivable Modifications, Post Modification Investment Recorded	$ 142	$ 92
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				2	10
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 30	$ 346
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 30	$ 344
Financing Receivable Modifications, Contracts, Number | loans	0	4
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 0	$ 120
Financing Receivable Modifications, Post Modification Investment Recorded	$ 0	$ 118
Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans				1	1
Financing Receivable, Troubled Debt Restructuring, Premodification				$ 0	$ 26
Financing Receivable, Troubled Debt Restructuring, Postmodification				$ 0	$ 15
Financing Receivable Modifications, Contracts, Number | loans	1	0
Financing Receivable Modifications, Pre Modification Investment Recorded	$ 0	$ 0
Financing Receivable Modifications, Post Modification Investment Recorded	$ 0	$ 0
Payment Deferral [Member] | Commercial segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans			90	20
Total restructured loans						312,500
Payment Deferral [Member] | Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans			53
Total restructured loans						$ 7,700