Commitments and Contingencies (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Loss Contingencies [Line Items]
Capital costs related to service lines in Puna	$ 0.5
Tropical Storm Iselle
Loss Contingencies [Line Items]
Estimate of possible loss	2.8
Expense recognized attributed to storm	$ 1.1

Amount of environmental remediation costs capitalized. These expenditures may relate to long-lived improvements in operating facilities.

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-Name Accounting Standards Codification

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates.

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