INVESTMENT SECURITIES - Continuous Unrealized Loss on Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
AFS
AFS, Less than 12 months, Gross unrealized losses	$ (91)	$ (579)
AFS, Less than 12 months, Fair value	15,120	135,407
AFS, Twelve months or more, Gross unrealized losses	(91,427)	(115,685)
AFS, Twelve months or more, Fair value	1,027,977	1,055,874
AFS, Total, Gross unrealized losses	(91,518)	(116,264)
AFS, Total, Fair value	1,043,097	1,191,281
Residential mortgage-backed securities
AFS
AFS, Less than 12 months, Gross unrealized losses	0	(3)
AFS, Less than 12 months, Fair value	0	1,145
AFS, Twelve months or more, Gross unrealized losses	(5,490)	(10,457)
AFS, Twelve months or more, Fair value	163,801	177,393
AFS, Total, Gross unrealized losses	(5,490)	(10,460)
AFS, Total, Fair value	163,801	178,538
Commercial mortgage-backed securities
AFS
AFS, Less than 12 months, Gross unrealized losses	0	0
AFS, Less than 12 months, Fair value	0	61
AFS, Twelve months or more, Gross unrealized losses	(5,602)	(7,479)
AFS, Twelve months or more, Fair value	49,178	47,695
AFS, Total, Gross unrealized losses	(5,602)	(7,479)
AFS, Total, Fair value	49,178	47,756
Residential collateralized mortgage obligations
AFS
AFS, Less than 12 months, Gross unrealized losses	0	(368)
AFS, Less than 12 months, Fair value	2,066	83,815
AFS, Twelve months or more, Gross unrealized losses	(25,080)	(33,171)
AFS, Twelve months or more, Fair value	319,501	348,914
AFS, Total, Gross unrealized losses	(25,080)	(33,539)
AFS, Total, Fair value	321,567	432,729
Commercial collateralized mortgage obligations
AFS
AFS, Less than 12 months, Gross unrealized losses	0	0
AFS, Less than 12 months, Fair value	0	0
AFS, Twelve months or more, Gross unrealized losses	(4,222)	(6,059)
AFS, Twelve months or more, Fair value	56,638	57,397
AFS, Total, Gross unrealized losses	(4,222)	(6,059)
AFS, Total, Fair value	56,638	57,397
Municipal bonds
AFS
AFS, Less than 12 months, Gross unrealized losses	(91)	(73)
AFS, Less than 12 months, Fair value	13,054	7,489
AFS, Twelve months or more, Gross unrealized losses	(42,059)	(47,780)
AFS, Twelve months or more, Fair value	357,312	364,775
AFS, Total, Gross unrealized losses	(42,150)	(47,853)
AFS, Total, Fair value	370,366	372,264
HTM
HFM, Less than 12 months, Gross unrealized losses	0	0
HFM, Less than 12 months, Fair value	0	0
HFM, 12 months or more, Gross unrealized losses	(22)	(40)
HFM, 12 months or more, Fair value	2,296	2,331
HFM, Total, Gross unrealized losses	(22)	(40)
HTM, Total, Fair value	2,296	2,331
Corporate debt securities
AFS
AFS, Less than 12 months, Gross unrealized losses	0	0
AFS, Less than 12 months, Fair value	0	0
AFS, Twelve months or more, Gross unrealized losses	(6,195)	(7,098)
AFS, Twelve months or more, Fair value	24,949	28,513
AFS, Total, Gross unrealized losses	(6,195)	(7,098)
AFS, Total, Fair value	24,949	28,513
U.S. Treasury securities
AFS
AFS, Less than 12 months, Gross unrealized losses	0	0
AFS, Less than 12 months, Fair value	0	0
AFS, Twelve months or more, Gross unrealized losses	(1,890)	(2,474)
AFS, Twelve months or more, Fair value	20,505	20,184
AFS, Total, Gross unrealized losses	(1,890)	(2,474)
AFS, Total, Fair value	20,505	20,184
Agency debentures
AFS
AFS, Less than 12 months, Gross unrealized losses	0	(135)
AFS, Less than 12 months, Fair value	0	42,897
AFS, Twelve months or more, Gross unrealized losses	(889)	(1,167)
AFS, Twelve months or more, Fair value	36,093	11,003
AFS, Total, Gross unrealized losses	(889)	(1,302)
AFS, Total, Fair value	$ 36,093	$ 53,900

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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