SECURITIES - Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Securities held-to-maturity:
Amortized Cost	$ 600,291	$ 585,798
Gross Unrecognized Losses	(104,305)	(80,039)
Fair Value	495,986	505,759
US Government Agencies Debt Securities [Member]
Securities held-to-maturity:
Amortized Cost	89,461	89,157
Gross Unrecognized Losses	(15,305)	(14,095)
Fair Value	74,156	75,062
Corporate Debt Securities [Member]
Securities held-to-maturity:
Amortized Cost	9,000	9,000
Gross Unrecognized Losses	(1,945)	(553)
Fair Value	7,055	8,447
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs")
Securities held-to-maturity:
Amortized Cost	283,258	278,281
Gross Unrecognized Losses	(53,777)	(40,960)
Fair Value	229,481	237,321
Agency collateralized mortgage obligations ("CMOs")
Securities held-to-maturity:
Amortized Cost	218,572	209,360
Gross Unrecognized Losses	(33,278)	(24,431)
Fair Value	$ 185,294	$ 184,929