REGULATORY ASSETS AND LIABILTIES - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liabilities	$ 683,717	$ 627,740
Accumulated depreciation and amortization	(1,152,228)	(1,063,341)
Regulatory balancing accounts	64,240	66,826
Regulatory balancing accounts	$ 21,540	12,240
Revision of Prior Period, Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liabilities		414,100
Accumulated depreciation and amortization		$ 414,100