General (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2023 USD ($)	Jun. 30, 2023 USD ($) member	Jun. 30, 2022 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of electric distribution cooperative members | member		38
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization, including nuclear fuel	$ 92,645	$ 196,729	$ 203,299
Property additions	285,233	$ 495,134	$ 526,406
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization, including nuclear fuel	26,100
Property additions	$ 26,100