INVESTMENT SECURITIES - Continuous Unrealized Loss on Investment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
AFS
AFS, Less than 12 months, Gross unrealized losses	$ (165)	$ (579)
AFS, Less than 12 months, Fair value	36,141	135,407
AFS, Twelve months or more, Gross unrealized losses	(121,390)	(115,685)
AFS, Twelve months or more, Fair value	1,077,172	1,055,874
AFS, Total, Gross unrealized losses	(121,555)	(116,264)
AFS, Total, Fair value	1,113,313	1,191,281
Residential mortgage-backed securities
AFS
AFS, Less than 12 months, Gross unrealized losses	(2)	(3)
AFS, Less than 12 months, Fair value	722	1,145
AFS, Twelve months or more, Gross unrealized losses	(10,879)	(10,457)
AFS, Twelve months or more, Fair value	171,977	177,393
AFS, Total, Gross unrealized losses	(10,881)	(10,460)
AFS, Total, Fair value	172,699	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	(7,613)	(7,479)
AFS, Twelve months or more, Fair value	47,470	47,695
AFS, Total, Gross unrealized losses	(7,613)	(7,479)
AFS, Total, Fair value	47,470	47,756
Residential collateralized mortgage obligations
AFS
AFS, Less than 12 months, Gross unrealized losses	(51)	(368)
AFS, Less than 12 months, Fair value	14,896	83,815
AFS, Twelve months or more, Gross unrealized losses	(35,465)	(33,171)
AFS, Twelve months or more, Fair value	346,156	348,914
AFS, Total, Gross unrealized losses	(35,516)	(33,539)
AFS, Total, Fair value	361,052	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	(6,000)	(6,059)
AFS, Twelve months or more, Fair value	56,702	57,397
AFS, Total, Gross unrealized losses	(6,000)	(6,059)
AFS, Total, Fair value	56,702	57,397
Municipal bonds
AFS
AFS, Less than 12 months, Gross unrealized losses	(109)	(73)
AFS, Less than 12 months, Fair value	15,526	7,489
AFS, Twelve months or more, Gross unrealized losses	(51,349)	(47,780)
AFS, Twelve months or more, Fair value	361,384	364,775
AFS, Total, Gross unrealized losses	(51,458)	(47,853)
AFS, Total, Fair value	376,910	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	(49)	(40)
HFM, 12 months or more, Fair value	2,305	2,331
HFM, Total, Gross unrealized losses	(49)	(40)
HTM, Total, Fair value	2,305	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	(6,012)	(7,098)
AFS, Twelve months or more, Fair value	25,147	28,513
AFS, Total, Gross unrealized losses	(6,012)	(7,098)
AFS, Total, Fair value	25,147	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	(2,675)	(2,474)
AFS, Twelve months or more, Fair value	19,896	20,184
AFS, Total, Gross unrealized losses	(2,675)	(2,474)
AFS, Total, Fair value	19,896	20,184
Agency debentures
AFS
AFS, Less than 12 months, Gross unrealized losses	(3)	(135)
AFS, Less than 12 months, Fair value	4,997	42,897
AFS, Twelve months or more, Gross unrealized losses	(1,397)	(1,167)
AFS, Twelve months or more, Fair value	48,440	11,003
AFS, Total, Gross unrealized losses	(1,400)	(1,302)
AFS, Total, Fair value	$ 53,437	$ 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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