PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 427,671	$ 414,170
Equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 61,519	60,536
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	30 years
Office buildings and other structures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 64,622	64,084
Useful life	30 years
Transmission and distribution plant
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 301,530	$ 289,550
Transmission and distribution plant | Minimum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Transmission and distribution plant | Maximum
Property, Plant and Equipment [Line Items]
Useful life	50 years