PENSION AND OTHER POSTRETIREMENT PLANS - Components of net periodic benefit cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net pension expense:
Net (gain) loss	$ 13	$ (115)	$ (390)
Pension Benefits
Net pension expense:
Service cost	0	0	0
Interest cost	75	53	52
Expected return on plan assets	(123)	(130)	(133)
Recognized net actuarial (gain) loss	18	99	160
Settlement cost	27	23	65
Net pension expense	(3)	45	144
Net (gain) loss	(43)	(215)	(350)
Amortization of net loss	(17)	(99)	(160)
Total recognized in other comprehensive income (loss)	(60)	(314)	(510)
Total recognized in net pension expense and other comprehensive income (loss)	$ (63)	$ (269)	$ (366)
Interest cost, location	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Expected return on plan assets, location	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
SERP Benefits
Net pension expense:
Service cost	$ 0	$ 0	$ 0
Interest cost	33	20	18
Expected return on plan assets	(38)	(45)	(47)
Recognized net actuarial (gain) loss	42	45	82
Settlement cost	0	0	0
Net pension expense	37	20	53
Net (gain) loss	56	100	(40)
Amortization of net loss	(42)	(45)	(82)
Total recognized in other comprehensive income (loss)	14	55	(122)
Total recognized in net pension expense and other comprehensive income (loss)	$ 51	$ 75	$ (69)
Interest cost, location	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Expected return on plan assets, location	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent