LOANS AND LEASES - Schedule of Loan and Lease Portfolio by Category (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 198,253	$ 192,629	$ 186,126	$ 171,869	$ 169,162	$ 151,861
Net loans and leases	12,945,948		12,583,202
Reverse mortgage, fair value	2,800		2,800	3,100
Financing Receivable Portfolio Segment, Including Reverse Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	13,144,201		12,769,328
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,639,152		2,540,070
Allowance for credit losses	56,516	55,902	49,394	52,400	53,473	49,526
Commercial | Owner-occupied commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,940,677		1,886,087
Allowance for credit losses	9,668	10,569	10,719	6,335	6,056	6,019
Commercial | Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	4,034,818		3,801,180
Allowance for credit losses	46,831	36,797	36,055	31,937	30,114	21,473
Commercial | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	879,217		1,035,530
Allowance for credit losses	9,198	10,959	10,762	9,228	9,672	6,987
Commercial | Commercial Small Business Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	643,520		623,622
Allowance for credit losses	16,218	15,459	15,170	10,383	9,236	9,868
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	900,384		870,705
Allowance for credit losses	5,057	5,407	5,483	5,043	5,327	4,668
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,106,433		2,012,134
Allowance for credit losses	$ 54,765	$ 57,536	$ 58,543	$ 56,543	$ 55,284	$ 53,320