INVESTMENT SECURITIES - Summary of Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Mar. 31, 2026 USD ($) security	Dec. 31, 2025 USD ($) security
Fair Value
Less than 12 Months	$ 111,763	$ 10,353
12 Months or Longer	1,160,251	1,257,538
Total	1,272,014	1,267,891
Gross Unrealized Losses
Less than 12 Months	(2,996)	(21)
12 Months or Longer	(188,832)	(168,726)
Total	$ (191,828)	$ (168,747)
Number of Securities | security	720	693
U.S. Government-sponsored agency securities
Fair Value
Less than 12 Months	$ 31	$ 0
12 Months or Longer	75,322	76,099
Total	75,353	76,099
Gross Unrealized Losses
Less than 12 Months	(1)	0
12 Months or Longer	(11,093)	(11,837)
Total	$ (11,094)	$ (11,837)
Number of Securities | security	13	12
State and municipal
Fair Value
Less than 12 Months	$ 98,417	$ 5,468
12 Months or Longer	772,574	861,410
Total	870,991	866,878
Gross Unrealized Losses
Less than 12 Months	(2,912)	(11)
12 Months or Longer	(112,946)	(91,830)
Total	$ (115,858)	$ (91,841)
Number of Securities | security	609	587
U.S. Government-sponsored mortgage-backed securities
Fair Value
Less than 12 Months	$ 12,325	$ 4,885
12 Months or Longer	305,646	313,353
Total	317,971	318,238
Gross Unrealized Losses
Less than 12 Months	(73)	(10)
12 Months or Longer	(64,547)	(64,783)
Total	$ (64,620)	$ (64,793)
Number of Securities | security	92	89
Corporate obligations
Fair Value
Less than 12 Months	$ 990	$ 0
12 Months or Longer	6,709	6,676
Total	7,699	6,676
Gross Unrealized Losses
Less than 12 Months	(10)	0
12 Months or Longer	(246)	(276)
Total	$ (256)	$ (276)
Number of Securities | security	6	5