SECURITIES - Schedule of Securities By Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Amortized Cost
Due in one year or less	$ 4,818
Due after one year through five years	7,298
Due after five years through ten years	38,103
Due after ten years	659,895
Total available-for-sale securities, gross	710,114
Mortgage-backed securities	531,807
Amortized Cost	1,241,921	$ 1,400,783
Fair Value
Due in one year or less	4,806
Due after one year through five years	6,422
Due after five years through ten years	33,697
Due after ten years	500,945
Total available-for-sale securities, gross	545,870
Mortgage-backed securities	429,662
Total securities available-for-sale	975,532	1,185,528
Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	129,494
Total held-to-maturity securities, gross	129,494
Mortgage-backed securities	0
Amortized Cost	129,494
Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	102,629
Total held-to-maturity securities, gross	102,629
Mortgage-backed securities	0
Fair Value	$ 102,629	$ 111,029