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INVESTMENT SECURITIES - Unrealized Gain/Loss on Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
AFS
Amortized cost	$ 1,208,542	$ 1,366,629
Gross unrealized gains	527	834
Gross unrealized losses	(91,518)	(116,264)
Fair value	1,117,551	1,251,199
Residential mortgage-backed securities
AFS
Amortized cost	179,214	194,141
Gross unrealized gains	180	117
Gross unrealized losses	(5,490)	(10,460)
Fair value	173,904	183,798
Commercial mortgage-backed securities
AFS
Amortized cost	54,780	55,235
Gross unrealized gains	0	0
Gross unrealized losses	(5,602)	(7,479)
Fair value	49,178	47,756
Residential collateralized mortgage obligations
AFS
Amortized cost	365,390	473,269
Gross unrealized gains	49	8
Gross unrealized losses	(25,080)	(33,539)
Fair value	340,359	439,738
Commercial collateralized mortgage obligations
AFS
Amortized cost	60,860	63,456
Gross unrealized gains	0	0
Gross unrealized losses	(4,222)	(6,059)
Fair value	56,638	57,397
Municipal bonds
AFS
Amortized cost	437,830	452,057
Gross unrealized gains	284	670
Gross unrealized losses	(42,150)	(47,853)
Fair value	395,964	404,874
HTM
Amortized cost	2,318	2,371
Gross unrealized gains	0	0
Gross unrealized losses	(22)	(40)
Fair value	2,296	2,331
Corporate debt securities
AFS
Amortized cost	41,144	45,611
Gross unrealized gains	11	34
Gross unrealized losses	(6,195)	(7,098)
Fair value	34,960	38,547
U.S. Treasury securities
AFS
Amortized cost	22,395	22,658
Gross unrealized gains	0	0
Gross unrealized losses	(1,890)	(2,474)
Fair value	20,505	20,184
Agency debentures
AFS
Amortized cost	46,929	60,202
Gross unrealized gains	3	5
Gross unrealized losses	(889)	(1,302)
Fair value	$ 46,043	$ 58,905

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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