COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($) dth	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Product Liability Contingency [Line Items]
Environmental trust liability		$ 27,733	$ 27,733	$ 27,400
Purchase commitment, energy volume required per day (in dekatherm) | dth	15,000,000
Purchase commitment per month	$ 200
Purchase commitment, termination notice period	12 months
Purchase commitment period	10 years
Landfill
Product Liability Contingency [Line Items]
Environmental liability		12,100	$ 12,100	10,500
Expense for updates to the post-closure cost estimates		1,600
Environmental liability related to landfill, period			30 years
Annual inflation rate on environmental liability related to landfill			3.00%
Coal Ash Impoundment
Product Liability Contingency [Line Items]
Environmental liability		$ 17,300	$ 17,300	$ 17,500
Environmental liability, remediation period			5 years