LOANS - Loan Summary (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans receivable, net
Gross loans, including deferred origination costs	$ 7,373,639	$ 7,415,952
Allowance for credit losses	(49,869)	(60,869)	$ (49,911)
Net loans	7,323,770	7,355,083
Net deferred loan origination costs	34,900	25,500
Loans receivable, related parties [Roll Forward]
Balance at beginning of year	15,549	17,486
New loans	2,500	4,194
Payments	(4,276)	(6,131)
Balance at end of year	13,773	15,549
Commercial Portfolio Segment \| Business Lending
Loans receivable, net
Gross loans, including deferred origination costs	3,075,904	3,440,077
Allowance for credit losses			(19,426)
Commercial Portfolio Segment \| Consumer Mortgage
Loans receivable, net
Allowance for credit losses			(10,269)
Residential Portfolio Segment \| Consumer Mortgage
Loans receivable, net
Gross loans, including deferred origination costs	2,556,114	2,401,499
Consumer Portfolio Segment \| Business Lending
Loans receivable, net
Allowance for credit losses	(21,021)	(28,190)
Consumer Portfolio Segment \| Consumer Mortgage
Loans receivable, net
Allowance for credit losses	(10,017)	(10,672)
Consumer Portfolio Segment \| Consumer Indirect
Loans receivable, net
Gross loans, including deferred origination costs	1,189,749	1,021,885
Allowance for credit losses	(11,737)	(13,696)	(13,712)
Consumer Portfolio Segment \| Consumer Direct
Loans receivable, net
Gross loans, including deferred origination costs	153,811	152,657
Allowance for credit losses	(2,306)	(3,207)	(3,255)
Consumer Portfolio Segment \| Home Equity
Loans receivable, net
Gross loans, including deferred origination costs	398,061	399,834
Allowance for credit losses	$ (1,814)	$ (2,222)	$ (2,129)

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Reflects the amount of new advances made to related parties in the form of loan and lease receivables.

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Amount of cash inflow from related parties which reduce the amount of loans and leases receivable due from related parties.

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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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