LOANS AND LEASES - Schedule of Loan and Lease Portfolio by Category (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 197,490	$ 198,253	$ 186,126	$ 175,988	$ 171,869	$ 151,861
Net loans and leases	13,124,684		12,583,202
Reverse mortgage, fair value	3,200		2,800	2,800
Financing Receivable Portfolio Segment, Including Reverse Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	13,322,174		12,769,328
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,639,266		2,540,070
Allowance for credit losses	56,795	56,516	49,394	51,678	52,400	49,526
Commercial | Owner-occupied commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,003,722		1,886,087
Allowance for credit losses	9,787	9,668	10,719	7,850	6,335	6,019
Commercial | Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	4,149,049		3,801,180
Allowance for credit losses	48,989	46,831	36,055	33,187	31,937	21,473
Commercial | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	805,857		1,035,530
Allowance for credit losses	8,348	9,198	10,762	11,317	9,228	6,987
Commercial | Commercial Small Business Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	645,421		623,622
Allowance for credit losses	15,374	16,218	15,170	9,992	10,383	9,868
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	940,780		870,705
Allowance for credit losses	5,463	5,057	5,483	5,351	5,043	4,668
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,138,079		2,012,134
Allowance for credit losses	$ 52,734	$ 54,765	$ 58,543	$ 56,613	$ 56,543	$ 53,320