INVESTMENT SECURITIES - Debt Maturities (Details) - Investment securities - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Amortized Cost
Due within one year	$ 567,615
Due after one year through five years	1,191,428
Due after five years through ten years	2,489,410
Due after ten years	811,682
Available-for-sale, amortized cost	5,060,135	$ 4,769,426
Fair Value
Due within one year	565,976
Due after one year through five years	1,173,923
Due after five years through ten years	2,386,411
Due after ten years	792,621
Total fair value	$ 4,918,931	$ 4,579,564
Weighted- Average Yield
Due within one year	1.75%
Due after one year through five years	4.25%
Due after five years through ten years	4.39%
Due after ten years	5.72%
Weighted-average yield	4.27%