INVESTMENT SECURITIES - Investments in Debt and Equity Securities Reported Less than Historical Cost (Details) - Investments reported at less than historical cost - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Schedule of Investments [Line Items]
Historical cost	$ 1,553,790	$ 1,592,597
Fair value	1,312,244	1,353,744
Gross unrealized losses	$ 241,546	$ 238,853
Percentage of the Corporation's investment securities available for sale in an unrealized loss position	95.20%	97.60%