v3.25.1
FAIR VALUE MEASUREMENTS AND DERIVATIVE INSTRUMENTS (Financial Impact of Derivative Energy Contracts) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Derivative Instruments, Gain (Loss) [Line Items]    
Percent of long-term trading contract gains shared with customers (percentage) 10.00%  
Operating Revenues $ 365,736 $ 452,756
Energy Derivative Contracts | Not Designated as Hedging Instrument    
Derivative Instruments, Gain (Loss) [Line Items]    
Unrealized Net Gain (Loss) (3,000) (14,000)
Operating Revenues $ 21,000 $ 27,000