Segment Reporting - Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 110,239	$ 118,859	$ 333,490	$ 343,112
Retail cost of revenues	71,050	102,212	234,417	232,621
Gross Profit	39,189	16,647	99,073	110,491
Less:
Net asset optimization (expense) revenue	(936)	1,672	(5,568)	(480)
Net, (loss) gain on non-trading derivative instruments	(6,991)	(1,645)	(50,428)	55,815
Current period settlements on non-trading derivatives	15,100	(14,078)	51,767	(35,922)
Non-recurring event - Winter Storm Uri	0	0	0	9,565
Retail Gross Margin	31,888	30,456	102,944	82,903
Total assets	297,076		297,076		$ 330,950
Goodwill	120,343		120,343		120,343
(Loss) gain on non-trading derivatives, net
Less:
Net, (loss) gain on non-trading derivative instruments	(6,193)	(1,413)	(49,002)	54,570
Current period settlements on non-trading derivatives	14,430	(14,068)	50,699	(36,067)
Operating Segments | Retail Electricity
Segment Reporting Information [Line Items]
Total revenues	97,855	104,970	255,447	275,301
Retail cost of revenues	64,575	92,816	183,017	189,092
Gross Profit	33,280	12,154	72,430	86,209
Less:
Net asset optimization (expense) revenue	0	0	0	0
Non-recurring event - Winter Storm Uri		0		9,565
Retail Gross Margin	25,991	28,507	69,454	62,404
Total assets	2,052,268		2,052,268		1,802,649
Goodwill	117,813		117,813		117,813
Operating Segments | Retail Electricity | (Loss) gain on non-trading derivatives, net
Less:
Net, (loss) gain on non-trading derivative instruments	(6,143)	(5,290)	(41,984)	42,557
Current period settlements on non-trading derivatives	13,432	(11,063)	44,960	(28,317)
Operating Segments | Retail Natural Gas
Segment Reporting Information [Line Items]
Total revenues	11,898	12,217	82,052	68,291
Retail cost of revenues	5,790	9,396	50,664	43,529
Gross Profit	6,108	2,821	31,388	24,762
Less:
Net asset optimization (expense) revenue	0	0	0	0
Non-recurring event - Winter Storm Uri		0		0
Retail Gross Margin	5,160	1,949	32,667	20,499
Total assets	164,076		164,076		123,490
Goodwill	2,530		2,530		2,530
Operating Segments | Retail Natural Gas | (Loss) gain on non-trading derivatives, net
Less:
Net, (loss) gain on non-trading derivative instruments	(50)	3,877	(7,018)	12,013
Current period settlements on non-trading derivatives	998	(3,005)	5,739	(7,750)
Corporate and Other
Segment Reporting Information [Line Items]
Total revenues	486	1,672	(4,009)	(480)
Retail cost of revenues	685	0	736	0
Gross Profit	(199)	1,672	(4,745)	(480)
Less:
Net asset optimization (expense) revenue	(936)	1,672		(480)
Non-recurring event - Winter Storm Uri		0		0
Retail Gross Margin	737	0	823	0
Total assets	299,577		299,577		313,490
Goodwill	0		0		0
Corporate and Other | (Loss) gain on non-trading derivatives, net
Less:
Net, (loss) gain on non-trading derivative instruments	0	0	0	0
Current period settlements on non-trading derivatives	0	0	0	0
Eliminations
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Retail cost of revenues	0	0	0	0
Gross Profit	0	0	0	0
Less:
Net asset optimization (expense) revenue	0	0	0	0
Non-recurring event - Winter Storm Uri		0		0
Retail Gross Margin	0	0	0	0
Total assets	(2,218,845)		(2,218,845)		(1,908,679)
Goodwill	0		0		$ 0
Eliminations | (Loss) gain on non-trading derivatives, net
Less:
Net, (loss) gain on non-trading derivative instruments	0	0	0	0
Current period settlements on non-trading derivatives	$ 0	$ 0	$ 0	$ 0