Revenues - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 3,075,344	$ 3,180,298	$ 3,248,505
Revenues from other sources	11,552	39,552	38,998
Total revenues	3,086,896	3,219,850	3,287,503
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,075,344	3,180,298	3,248,505
Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,061,675	3,168,375	3,230,965
Revenues from other sources	9,507	38,325	38,556
Total revenues	3,071,182	3,206,700	3,269,521
Electric utility | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,061,675	3,168,375	3,230,965
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,669	11,923	17,540
Revenues from other sources	2,045	1,227	442
Total revenues	15,714	13,150	17,982
Other | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,669	11,923	17,540
Electric energy sales - residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	992,367	1,012,620	1,026,321
Electric energy sales - residential | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	992,367	1,012,620	1,026,321
Electric energy sales - residential | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Electric energy sales - commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	971,816	1,013,189	1,044,045
Electric energy sales - commercial | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	971,816	1,013,189	1,044,045
Electric energy sales - commercial | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Electric energy sales - large light and power
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,079,522	1,123,884	1,141,128
Electric energy sales - large light and power | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,079,522	1,123,884	1,141,128
Electric energy sales - large light and power | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Electric energy sales - other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	17,970	18,682	19,471
Electric energy sales - other | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	17,970	18,682	19,471
Electric energy sales - other | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Other sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,669	11,923	17,540
Other sales | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Other sales | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,669	11,923	17,540
Regulatory revenue
Disaggregation of Revenue [Line Items]
Revenues from other sources	(29,471)	(2,566)	3,708
Regulatory revenue | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from other sources	(29,471)	(2,566)	3,708
Regulatory revenue | Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0	0
Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	41,023	42,118	35,290
Other | Electric utility
Disaggregation of Revenue [Line Items]
Revenues from other sources	38,978	40,891	34,848
Other | Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	$ 2,045	$ 1,227	$ 442