Derivative Instruments (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Asset derivatives:
Derivative instruments, at fair value	$ 66,408	$ 107,647
Liability derivatives:
Derivative instruments, at fair value	58,116	29,651
Margin deposits received (remitted to) counterparties	(100)	(300)
Commodity derivatives
Asset derivatives:
Derivative instruments, at fair value	66,408	107,647
Derivative instruments subject to master netting agreements	(26,331)	(20,843)
Derivative instruments, net	40,077	86,804
Liability derivatives:
Derivative instruments, at fair value	58,116	29,651
Derivative instruments subject to master netting agreements	(26,331)	(20,843)
Margin deposits received (remitted to) counterparties	(103)	(266)
Derivative instruments, net	$ 31,682	$ 8,542

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.

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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.

+ References

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-Publisher FASB

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Fair value of 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, elected not to be offset against an obligation to return collateral under a master netting arrangement.

+ References

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

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Fair value before effects of master netting arrangements, of a financial liability or 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.

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Fair value of financial liability or 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, elected not to be offset against a right to receive collateral under a master netting arrangement.

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Fair value of asset associated with financial liability or 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.

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The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

+ References

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

-Publisher FASB

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