Customer Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Number of purchase agreements	2
Variable rate electricity contracts	13,400	13,400
Customer Contracts
Finite-Lived Intangible Assets [Line Items]
Purchase price	$ 2.2	$ 2.2
Amortization period	3 years	3 years
Intangible assets paid and capitalized	$ 1.5	$ 1.5