ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 88,623	$ 62,558	$ 252,325	$ 164,214
Net securities gains (losses)	(35)	0	(16)	0
Income tax expense	4,479	6,237	10,130	16,360
Other expense	2,609	3,724	7,742	10,262
Net income	25,252	28,525	64,141	77,840
Amount Reclassified From Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(434)	(425)	(1,219)	(867)
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Debt Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	113		316
Net income	(423)		(1,186)
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Held-to-Maturity Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	(501)	(504)	(1,486)	(995)
Income tax expense		106		209
Net income		(398)		(786)
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (losses)	(35)		(16)
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	4	9	12	27
Other expense	(15)	(36)	(45)	(108)
Net income	$ (11)	$ (27)	$ (33)	$ (81)