LOANS AND LEASES - Additional Information (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) state	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable	$ 139,200,000		$ 128,600,000
Discount remaining	$ 38,400,000		42,600,000
Number of states, company operating financial services | state	7
Loan modification, accrued interest receivable	$ 10,000.00	$ 20,000.00
Loan modification, additional funds	0
Pooled reserves for all other classes of loans	$ 3,800,000		3,800,000
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due period for loan to be in default	90 days
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due period for loan to be in default	12 months
Total commercial loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified, specific reserves	$ 500,000		5,300,000
Loans modified, pooled reserves	2,500,000		2,000,000
Total commercial loans and leases | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, collateral dependent	63,600,000
Threshold for loans whose terms have been modified in a trouble debt restructuring, non accrual	1,000,000
Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of OREO through foreclosure	1,300,000		1,200,000
Mortgage loans on real estate, foreclosure	$ 13,100,000		$ 9,400,000