LOANS AND LEASES - Schedule of Loan and Lease Portfolio by Category (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 177,263	$ 180,011	$ 179,647	$ 186,304	$ 187,515	$ 195,281
Net loans and leases	13,289,859		13,082,027
Reverse mortgage, fair value	4,000		3,700	4,700
Financing Receivable Portfolio Segment, Including Reverse Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	13,467,122		13,261,674
Commercial \| Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	3,013,715		2,796,654
Allowance for credit losses	51,883	51,312	52,927	52,121	50,736	57,131
Commercial \| Owner-occupied commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,930,367		1,937,339
Allowance for credit losses	8,717	8,168	7,626	8,584	8,410	9,139
Commercial \| Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	3,883,849		3,916,159
Allowance for credit losses	49,451	48,816	48,047	54,775	49,792	48,962
Commercial \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,002,999		1,023,911
Allowance for credit losses	13,541	13,870	13,264	10,696	9,691	9,185
Commercial \| Commercial Small Business Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	584,175		603,321
Allowance for credit losses	17,424	15,840	16,449	18,301	17,109	15,965
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,236,779		1,089,830
Allowance for credit losses	6,260	7,330	6,764	5,815	5,697	5,566
Consumer(3)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,815,238		1,894,460
Allowance for credit losses	$ 29,987	$ 34,675	$ 34,570	$ 36,012	$ 46,080	$ 49,333