SECURITIES - Available-for-sale (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Securities available-for-sale:
Amortized Cost	$ 1,028,273	$ 1,071,858
Gross Unrealized Gains	2	59
Gross Unrealized Losses	(133,419)	(121,330)
Fair Value	894,856	950,587
Agency Notes
Securities available-for-sale:
Amortized Cost	10,000
Gross Unrealized Losses	(855)
Fair Value	9,145
Treasury Securities
Securities available-for-sale:
Amortized Cost	246,392	246,899
Gross Unrealized Losses	(17,785)	(19,643)
Fair Value	228,607	227,256
Corporate Securities
Securities available-for-sale:
Amortized Cost	169,589	183,791
Gross Unrealized Gains		57
Gross Unrealized Losses	(30,036)	(17,075)
Fair Value	139,553	166,773
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs")
Securities available-for-sale:
Amortized Cost	253,191	272,774
Gross Unrealized Losses	(30,607)	(31,534)
Fair Value	222,584	241,240
Agency collateralized mortgage obligations ("CMOs")
Securities available-for-sale:
Amortized Cost	317,307	331,394
Gross Unrealized Gains	2	2
Gross Unrealized Losses	(51,636)	(50,057)
Fair Value	265,673	281,339
State and municipal obligations.
Securities available-for-sale:
Amortized Cost	31,794	37,000
Gross Unrealized Losses	(2,500)	(3,021)
Fair Value	$ 29,294	$ 33,979