INVESTMENT SECURITIES - Summary of Amortized Cost of Investment Securities Held to Maturity Aggregated by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Schedule of Held-to-maturity Securities [Line Items]
Total	$ 2,023,071	$ 2,074,465
Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	1,041,537	1,107,845
Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	179,548	148,923
Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	176,970	184,341
Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	183,941	185,166
A1
Schedule of Held-to-maturity Securities [Line Items]
Total	65,652	65,665
A2
Schedule of Held-to-maturity Securities [Line Items]
Total	20,325	20,317
Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	355,098	362,208
U.S. Government-sponsored agency securities
Schedule of Held-to-maturity Securities [Line Items]
Total	334,970	345,531
U.S. Government-sponsored agency securities \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	334,970	345,531
U.S. Government-sponsored agency securities \| Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored agency securities \| Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored agency securities \| Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored agency securities \| A1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored agency securities \| A2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored agency securities \| Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
State and municipal
Schedule of Held-to-maturity Securities [Line Items]
Total	1,076,773	1,085,921
State and municipal \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	96,739	120,801
State and municipal \| Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	179,548	148,923
State and municipal \| Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	176,970	184,341
State and municipal \| Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	183,941	185,166
State and municipal \| A1
Schedule of Held-to-maturity Securities [Line Items]
Total	65,652	65,665
State and municipal \| A2
Schedule of Held-to-maturity Securities [Line Items]
Total	20,325	20,317
State and municipal \| Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	353,598	360,708
U.S. Government-sponsored mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Total	609,828	641,513
U.S. Government-sponsored mortgage-backed securities \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	609,828	641,513
U.S. Government-sponsored mortgage-backed securities \| Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored mortgage-backed securities \| Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored mortgage-backed securities \| Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored mortgage-backed securities \| A1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored mortgage-backed securities \| A2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
U.S. Government-sponsored mortgage-backed securities \| Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment
Schedule of Held-to-maturity Securities [Line Items]
Total	1,500	1,500
Foreign investment \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| A1
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| A2
Schedule of Held-to-maturity Securities [Line Items]
Total	0	0
Foreign investment \| Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	$ 1,500	$ 1,500