Derivative and Hedging Instruments (Details-2) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Commodity Derivative Contracts [Member]
Offsetting Assets [Line Items]
Gross amounts	$ 525	$ 223
Gross amounts offset in balance sheet	(525)	(223)
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	0	0
Financial Transmission Rights [Member]
Offsetting Assets [Line Items]
Gross amounts	813	642
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 813	$ 642

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

+ References

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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