INVESTMENT SECURITIES - Summary of Amortized Cost of Investment Securities Held to Maturity Aggregated by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Schedule of Held-to-maturity Securities [Line Items]
Total	$ 1,907,929	$ 1,971,784
Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	923,149	977,729
Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	206,330	200,189
Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	161,487	172,127
Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	195,134	192,682
A1
Schedule of Held-to-maturity Securities [Line Items]
Total	59,625	59,631
A2
Schedule of Held-to-maturity Securities [Line Items]
Total	10,190	13,664
A3
Schedule of Held-to-maturity Securities [Line Items]
Total	10,153	6,670
Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	341,861	349,092
U.S. Government-sponsored agency securities
Schedule of Held-to-maturity Securities [Line Items]
Total	313,105	324,643
U.S. Government-sponsored agency securities \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	313,105	324,643
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 \| A3
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	1,058,396	1,069,653
State and municipal \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	73,616	75,598
State and municipal \| Aa1
Schedule of Held-to-maturity Securities [Line Items]
Total	206,330	200,189
State and municipal \| Aa2
Schedule of Held-to-maturity Securities [Line Items]
Total	161,487	172,127
State and municipal \| Aa3
Schedule of Held-to-maturity Securities [Line Items]
Total	195,134	192,682
State and municipal \| A1
Schedule of Held-to-maturity Securities [Line Items]
Total	59,625	59,631
State and municipal \| A2
Schedule of Held-to-maturity Securities [Line Items]
Total	10,190	13,664
State and municipal \| A3
Schedule of Held-to-maturity Securities [Line Items]
Total	10,153	6,670
State and municipal \| Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Total	341,861	349,092
U.S. Government-sponsored mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Total	536,428	577,488
U.S. Government-sponsored mortgage-backed securities \| Aaa
Schedule of Held-to-maturity Securities [Line Items]
Total	536,428	577,488
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 \| A3
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