SECURITIES - Amortized Cost and Fair Value By Contractual Maturity, Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Held-to-maturity, Amortized Cost
One to five years	$ 19,772
Five to ten years	78,689
Pass-through MBS issued by GSEs and agency CMO	501,830
Total Amortized Cost	600,291
Held-to-maturity, Fair Value
One to five years	17,743
Five to ten years	63,468
Pass-through MBS issued by GSEs and agency CMO	414,775
Total Fair Value	$ 495,986	$ 505,759