ACCUMULATED OTHER COMPREHENSIVE INCOME - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 84,482	$ 53,622	$ 163,702	$ 101,656
Net securities gains	3	0	19	0
Income tax expense	1,880	5,584	5,651	10,123
Other expense	2,571	3,299	5,133	6,538
Net income	14,611	25,673	38,889	49,315
Amount Reclassified From Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(399)	(332)	(785)	(359)
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	3		19
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Held-to-Maturity Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	(494)	(386)	(985)	(386)
Income tax expense	103	81	203	81
Net income	(388)	(305)	(763)	(305)
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	8	18
Other expense	(15)	(36)	(30)	(72)
Net income	$ (11)	$ (27)	$ (22)	$ (54)