Revenues - Schedule of Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Net asset optimization expense	$ (2,249)	$ (1,597)
Total Revenues	142,257	114,056
Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	144,503	114,388
Other revenue
Disaggregation of Revenue [Line Items]
Retail revenues	3	1,265
POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	84,900	69,758
Non-POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	59,603	44,630
Unbilled revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	(6,064)	(7,280)
Commercial | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	45,847	32,079
Residential | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	104,720	89,589
New England | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	26,467	31,964
Mid-Atlantic | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	59,084	45,954
Midwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	20,338	14,680
Southwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	38,614	21,790
Retail Electricity | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	80,720	77,329
Retail Electricity | POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	55,934	50,289
Retail Electricity | Non-POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	24,786	27,040
Retail Electricity | Unbilled revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	(6,298)	(4,984)
Retail Electricity | Commercial | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	10,801	11,365
Retail Electricity | Residential | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	76,217	70,948
Retail Electricity | New England | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	21,272	27,339
Retail Electricity | Mid-Atlantic | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	38,860	30,699
Retail Electricity | Midwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	8,119	7,309
Retail Electricity | Southwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	12,469	11,982
Retail Natural Gas | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	63,783	37,059
Retail Natural Gas | POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	28,966	19,469
Retail Natural Gas | Non-POR | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	34,817	17,590
Retail Natural Gas | Unbilled revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	234	(2,296)
Retail Natural Gas | Commercial | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	35,046	20,714
Retail Natural Gas | Residential | Billed Revenue | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	28,503	18,641
Retail Natural Gas | New England | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	5,195	4,625
Retail Natural Gas | Mid-Atlantic | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	20,224	15,255
Retail Natural Gas | Midwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	12,219	7,371
Retail Natural Gas | Southwest | Retail revenues
Disaggregation of Revenue [Line Items]
Retail revenues	$ 26,145	$ 9,808