INVESTMENT SECURITIES - Schedule of Gross Unrealized Losses and Fair Value of Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Estimated Fair Value
Less Than 12 Months	$ 152,501	$ 162,258
12 Months or More	1,208,344	1,154,553
Total	1,360,845	1,316,811
Unrealized Losses
Less Than 12 Months	(887)	(827)
12 Months or More	(47,284)	(43,909)
Total	(48,171)	(44,736)
U.S. Treasuries
Estimated Fair Value
Less Than 12 Months	28,673	159,667
12 Months or More	656,429	537,313
Total	685,102	696,980
Unrealized Losses
Less Than 12 Months	(354)	(827)
12 Months or More	(9,850)	(10,966)
Total	(10,204)	(11,793)
U.S. government-sponsored agencies
Estimated Fair Value
Less Than 12 Months	0	0
12 Months or More	981	985
Total	981	985
Unrealized Losses
Less Than 12 Months	0	0
12 Months or More	(35)	(38)
Total	(35)	(38)
State, county and municipal securities
Estimated Fair Value
Less Than 12 Months	5,930	1,923
12 Months or More	19,545	19,754
Total	25,475	21,677
Unrealized Losses
Less Than 12 Months	(31)	0
12 Months or More	(1,257)	(944)
Total	(1,288)	(944)
Corporate debt securities
Estimated Fair Value
Less Than 12 Months	499	500
12 Months or More	8,502	8,527
Total	9,001	9,027
Unrealized Losses
Less Than 12 Months	(1)	0
12 Months or More	(876)	(850)
Total	(877)	(850)
SBA pool securities
Estimated Fair Value
Less Than 12 Months	57,303	42
12 Months or More	18,815	21,267
Total	76,118	21,309
Unrealized Losses
Less Than 12 Months	(68)	0
12 Months or More	(1,519)	(1,519)
Total	(1,587)	(1,519)
Mortgage-backed securities
Estimated Fair Value
Less Than 12 Months	60,096	126
12 Months or More	504,072	566,707
Total	564,168	566,833
Unrealized Losses
Less Than 12 Months	(433)	0
12 Months or More	(33,747)	(29,592)
Total	$ (34,180)	$ (29,592)