ACCUMULATED OTHER COMPREHENSIVE INCOME - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 53,622	$ 47,625	$ 101,656	$ 95,602
Net securities gains	0	44	0	797
Income tax expense	5,584	5,705	10,123	10,735
Other expense	3,299	1,904	6,538	4,148
Net income	25,673	24,348	49,315	47,331
Amount Reclassified From Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(332)	(10)	(359)	540
Amount Reclassified From Accumulated Other Comprehensive Income | Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains		44		797
Income tax expense		(9)		(167)
Net income		35		630
Amount Reclassified From Accumulated Other Comprehensive Income | Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	9	15	18	30
Other expense	(36)	(60)	(72)	(120)
Net income	(27)	$ (45)	(54)	$ (90)
Amount Reclassified From Accumulated Other Comprehensive Income | Held-to-Maturity Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	(386)		(386)
Income tax expense	81		81
Net income	$ (305)		$ (305)