Derivative Financial Instruments (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative Liabilities
Counterparty set-off	$ 31,548	$ 13,258
Total derivative liability net fair value	(6,914)us-gaap_DerivativeLiabilities	(22,897)us-gaap_DerivativeLiabilities
Short term derivative liabilities
Derivative Liabilities
Liabilities	(4,645)	(14,451)
Assets	(31,548)	(8,052)
Liability fair value	(36,193)	(22,503)
Long Term derivative liabilities
Derivative Liabilities
Liabilities	(2,269)	(11,496)
Liability fair value	(2,269)	(13,652)
Other assets
Derivative Liabilities
Assets		$ (2,156)

Fair value, after offset of derivative asset, 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 and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value, after the 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. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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