LOANS AND ALLOWANCE FOR CREDIT LOSSES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income on nonaccrual loans	$ 0	$ 0
Loans, net of unearned income	20,600,260		$ 20,269,303
Unfunded commitments	4,053	$ 843
Unfunded Loan Commitments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded commitments	446		1,500
9
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0		0
Loan Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable	$ 77,400		$ 79,200