v2.4.0.8

Derivative Financial Instruments Schedule of Derivative Offset Amounts (Details) (Exchange Traded [Member], USD $) In Thousands, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Derivative [Line Items] |  |
Derivative Liability, Fair Value, Gross Liability | $ (3,439) | $ (7,167)
Derivative Asset, Fair Value, Gross Asset | 1,534 | 2,665
Derivative Liability Amount Not Offset | (1,905) | (4,502)
Derivative Liability, Fair Value of Collateral | 12,714 | 14,782
Margin Deposit Net of Commodity Contract | 10,809 | 10,280
Other Current Liabilities [Member] |  |
Derivative [Line Items] |  |
Derivative Liability Amount Not Offset | (3,421) | (6,737)
Other Noncurrent Assets [Member] |  |
Derivative [Line Items] |  |
Derivative Liability Amount Not Offset | $ 1,516 | $ 2,235

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