Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities (Potential Impact of Rights of Offset Associated with Recognized Assets and Liabilities) (Details)

v2.4.0.8
Derivative Instruments and Hedging Activities (Potential Impact of Rights of Offset Associated with Recognized Assets and Liabilities) (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Offsetting Assets and Liabilities [Line Items]    
Derivative Assets, Current $ 1,647 $ 1,674
Current assets: Fair value of hedging contracts [Member] | Hedging Contracts [Member]
   
Offsetting Assets and Liabilities [Line Items]    
Derivative Asset, Fair Value, Gross Asset 2,330  
Derivative Asset, Collateral, Obligation to Return Cash, Offset (683)  
Derivative Asset, Fair Value, Amount Offset Against Collateral 1,647  
Long-term assets: Fair value of hedging contracts [Member] | Hedging Contracts [Member]
   
Offsetting Assets and Liabilities [Line Items]    
Derivative Asset, Fair Value, Gross Asset 852  
Derivative Asset, Collateral, Obligation to Return Cash, Offset (424)  
Derivative Asset, Fair Value, Amount Offset Against Collateral 428  
Current liabilities: Fair value of hedging contracts [Member] | Hedging Contracts [Member]
   
Offsetting Assets and Liabilities [Line Items]    
Derivative Liability, Fair Value, Gross Liability (789)  
Derivative Liability, Collateral, Right to Reclaim Cash, Offset 683  
Derivative Liability, Fair Value, Amount Offset Against Collateral 106  
Long-term liabilities: Fair value of hedging contracts [Member] | Hedging Contracts [Member]
   
Offsetting Assets and Liabilities [Line Items]    
Derivative Liability, Fair Value, Gross Liability (462)  
Derivative Liability, Collateral, Right to Reclaim Cash, Offset 424  
Derivative Liability, Fair Value, Amount Offset Against Collateral $ 38