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INVESTMENT SECURITIES - Unrealized Gain/Loss on Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
AFS
Amortized cost	$ 1,427,111	$ 975,763
Gross unrealized gains	138	30,084
Gross unrealized losses	(139,522)	(3,325)
Fair value	1,287,727	1,002,522
Residential mortgage-backed securities
AFS
Amortized cost	208,807	32,905
Gross unrealized gains	0	396
Gross unrealized losses	(9,817)	(338)
Fair value	198,990	32,963
Commercial mortgage-backed securities
AFS
Amortized cost	68,706	62,094
Gross unrealized gains	0	933
Gross unrealized losses	(9,834)	(235)
Fair value	58,872	62,792
Residential collateralized mortgage obligations
AFS
Amortized cost	489,223	186,703
Gross unrealized gains	12	2,012
Gross unrealized losses	(36,021)	(1,321)
Fair value	453,214	187,394
Commercial collateralized mortgage obligations
AFS
Amortized cost	97,886	135,102
Gross unrealized gains	0	1,890
Gross unrealized losses	(7,025)	(333)
Fair value	90,861	136,659
Municipal bonds
AFS
Amortized cost	498,665	516,693
Gross unrealized gains	121	24,154
Gross unrealized losses	(70,589)	(924)
Fair value	428,197	539,923
HTM
Amortized cost	3,099	4,169
Gross unrealized gains	0	136
Gross unrealized losses	(101)	0
Fair value	2,998	4,305
Corporate debt securities
AFS
Amortized cost	36,733	18,918
Gross unrealized gains	0	699
Gross unrealized losses	(2,971)	(1)
Fair value	33,762	19,616
U.S. Treasury securities
AFS
Amortized cost	23,092	23,348
Gross unrealized gains	0	0
Gross unrealized losses	(3,265)	(173)
Fair value	19,827	$ 23,175
Agency debentures
AFS
Amortized cost	3,999
Gross unrealized gains	5
Gross unrealized losses	0
Fair value	$ 4,004

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