Customer Acquisitions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2015 USD ($) contract	Dec. 31, 2014 USD ($) agreement contract	Dec. 31, 2015 USD ($)
Finite-Lived Intangible Assets [Line Items]
Intangible assets paid and capitalized			$ 14,623
Customer Relationships | Northern California
Finite-Lived Intangible Assets [Line Items]
Residential and commercial natural gas contracts | contract	25,800
Contract purchase price	$ 2,000
Amortization period	3 years
Customer Relationships | Connecticut
Finite-Lived Intangible Assets [Line Items]
Contract purchase price		$ 2,200
Amortization period		3 years
Number of purchase agreements | agreement		2
Variable rate electricity contracts | contract		13,400
Intangible assets paid and capitalized		$ 1,500