INVESTMENT SECURITIES - Amortized Cost of Investment Securities Held to Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Held-to-maturity Securities [Line Items]
Total	$ 2,134,440	$ 2,184,497
Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	183,929
Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	161,380
Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	167,506
Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	133,319
A1
Schedule of Held-to-maturity Securities [Line Items]
Total	131,193
A2
Schedule of Held-to-maturity Securities [Line Items]
Total	16,839
A3
Schedule of Held-to-maturity Securities [Line Items]
Total	3,470
Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	1,336,804
State and municipal
Schedule of Held-to-maturity Securities [Line Items]
Total	1,091,714	$ 1,099,201
State and municipal | Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	113,341
State and municipal | Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	161,380
State and municipal | Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	167,506
State and municipal | Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	133,319
State and municipal | A1
Schedule of Held-to-maturity Securities [Line Items]
Total	131,193
State and municipal | A2
Schedule of Held-to-maturity Securities [Line Items]
Total	16,839
State and municipal | A3
Schedule of Held-to-maturity Securities [Line Items]
Total	3,470
State and municipal | Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	364,666
Other
Schedule of Held-to-maturity Securities [Line Items]
Total	1,042,726
Other | Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	70,588
Other | Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | A1
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | A2
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | A3
Schedule of Held-to-maturity Securities [Line Items]
Total	0
Other | Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	$ 972,138