INVESTMENT SECURITIES - Schedule of Maturities of Investment Securities Available-for-Sale and Held-to-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Available for Sale Amortized Cost
Within one year	$ 0	$ 0
After one year but within five years	86,224	83,014
After five years but within ten years	569,956	465,777
After ten years	3,848,162	4,285,759
Amortized Cost	4,504,342	4,834,550
Available for Sale Fair Value
Within one year	0	0
After one year but within five years	82,387	77,499
After five years but within ten years	485,593	398,607
After ten years	3,278,557	3,616,954
Fair Value	3,846,537	4,093,060
Held to Maturity, Amortized Cost
Within one year	0	731
After one year but within five years	10,932	9,530
After five years but within ten years	46,489	46,170
After ten years	1,001,144	1,055,198
Past due held-to-maturity debt securities	1,058,565	1,111,629
Held to Maturity, Fair Value
Within one year	0	732
After one year but within five years	10,856	9,476
After five years but within ten years	46,246	45,944
After ten years	928,829	983,952
Fair Value	$ 985,931	$ 1,040,104