Segment Reporting - Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total Revenues	$ 91,267	$ 68,217	$ 263,313	[1]	$ 240,134
Retail cost of revenues	60,967	51,863	176,000	[1]	192,371
Optimization Revenues - Affiliates	(545)	(141)	1,317	[1]	1,681
Current period settlements on derivatives			15,120	[1]	(7,252)
Retail gross margin	26,678	14,619	79,229		50,194
Total Assets	160,453	122,074	160,453		122,074	$ 138,397
Not Designated as Hedging Instrument
Segment Reporting Information [Line Items]
Gain (Loss) on derivatives, net	132	(1,163)	(5,876)		5,847
Current period settlements on derivatives	4,035	3,039	12,643		(9,959)
Operating Segments | Retail Electricity
Segment Reporting Information [Line Items]
Total Revenues	76,913	51,748	170,060		137,968
Retail cost of revenues	50,787	41,628	122,864		114,997
Optimization Revenues - Affiliates	0	0	0		0
Retail gross margin	18,925	6,769	43,670		24,519
Total Assets	147,037	47,677	147,037		47,677
Operating Segments | Retail Electricity | Not Designated as Hedging Instrument
Segment Reporting Information [Line Items]
Gain (Loss) on derivatives, net	3,891	445	(2,201)		6,037
Current period settlements on derivatives	3,310	2,906	5,727		(7,585)
Operating Segments | Retail Natural Gas
Segment Reporting Information [Line Items]
Total Revenues	14,354	16,469	93,253		102,166
Retail cost of revenues	10,180	10,235	53,136		77,374
Optimization Revenues - Affiliates	(545)	(141)	1,317		1,681
Retail gross margin	7,753	7,850	35,559		25,675
Total Assets	101,844	92,974	101,844		92,974
Operating Segments | Retail Natural Gas | Not Designated as Hedging Instrument
Segment Reporting Information [Line Items]
Gain (Loss) on derivatives, net	(3,759)	(1,608)	(3,675)		(190)
Current period settlements on derivatives	725	133	6,916		(2,374)
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Total Revenues	0	0	0		0
Retail cost of revenues	0	0	0		0
Optimization Revenues - Affiliates	0	0	0		0
Retail gross margin	0	0	0		0
Total Assets	96,319	20,309	96,319		20,309
Corporate, Non-Segment | Not Designated as Hedging Instrument
Segment Reporting Information [Line Items]
Gain (Loss) on derivatives, net	0	0	0		0
Current period settlements on 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
Optimization Revenues - Affiliates	0	0	0		0
Retail gross margin	0	0	0		0
Total Assets	(184,747)	(38,886)	(184,747)		(38,886)
Eliminations | Not Designated as Hedging Instrument
Segment Reporting Information [Line Items]
Gain (Loss) on derivatives, net	0	0	0		0
Current period settlements on derivatives	$ 0	$ 0	$ 0		$ 0

[1] Financial information has been recast to include results attributable to the acquisition of Oasis Power Holdings LLC on May 12, 2015 from an affiliate. See Note 2 “Basis of Presentation” and Note 3 "Acquisitions" for further discussion.