INVESTMENT SECURITIES - Amortized Cost and Fair Value of Available for Sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized Cost
Due in one year or less	$ 282,084
Due from one year to five years	382,895
Due from five to ten years	69,328
Due after ten years	11,572
Mortgage-backed securities	713,439
Amortized Cost	1,459,318	$ 1,447,637
Estimated Fair Value
Due in one year or less	279,670
Due from one year to five years	383,492
Due from five to ten years	68,345
Due after ten years	10,506
Mortgage-backed securities	699,539
Estimated Fair Value	1,441,552	1,402,944
Amortized Cost
Due in one year or less	0
Due from one year to five years	0
Due from five to ten years	0
Due after ten years	33,648
Mortgage-backed securities	127,572
Amortized Cost	161,220	141,512
Estimated Fair Value
Due in one year or less	0
Due from one year to five years	0
Due from five to ten years	0
Due after ten years	28,741
Mortgage-backed securities	116,973
Estimated Fair Value	$ 145,714	$ 122,731