v2.4.0.8
Derivative Financial Instruments Schedule of Derivative Offset Amounts (Details) (Exchange Traded [Member], USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Derivative [Line Items]    
Derivative Asset, Fair Value, Gross Asset $ 31,909 $ 2,665
Derivative Liability, Fair Value, Gross Liability (4,222) (7,167)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral   (4,502)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 27,687  
Derivative Liability, Fair Value of Collateral 133 14,782
Margin Deposit Net of Commodity Contract   10,280
Excess Margin Deposit 27,820  
Other Current Liabilities [Member]
    
Derivative [Line Items]    
Derivative Liability, Fair Value, Amount Not Offset Against Collateral   (6,737)
Other Noncurrent Liabilities [Member]
    
Derivative [Line Items]    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral (70)  
Other Noncurrent Assets [Member]
    
Derivative [Line Items]    
Derivative Liability, Fair Value, Amount Not Offset Against Collateral   2,235
Other Current Assets [Member]
    
Derivative [Line Items]    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral $ 27,757