ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of net loss	$ 4,252	$ 11,474	$ 12,453	$ 22,948
Amortization of unrecognized prior service cost	72	(70)	82	(140)
Reclassification adjustment, before tax and regulatory adjustments	4,324	11,404	12,535	22,808
Regulatory adjustments	(4,265)	(11,014)	(12,388)	(22,027)
Reclassification adjustment, before tax	59	390	147	781
Reclassification adjustment, Tax	(15)	(91)	(34)	(182)
Reclassification adjustment, net of tax	$ 44	$ 299	$ 113	$ 599