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)

v2.4.0.6
Derivative Instruments and Hedging Activities (Potential Impact of Rights of Offset Associated with Recognized Assets and Liabilities) (Details) (Hedging Contracts [Member], USD $)
In Thousands, unless otherwise specified
Mar. 31, 2013
Current assets: Fair value of hedging contracts [Member]
 
Offsetting Assets and Liabilities [Line Items]  
Derivative Asset, Fair Value, Gross Asset $ 2,347
Derivative Asset, Collateral, Obligation to Return Cash, Offset (836)
Derivative Asset, Fair Value, Amount Offset Against Collateral 1,511
Long-term assets: Fair value of hedging contracts [Member]
 
Offsetting Assets and Liabilities [Line Items]  
Derivative Asset, Fair Value, Gross Asset 286
Derivative Asset, Collateral, Obligation to Return Cash, Offset (286)
Derivative Asset, Fair Value, Amount Offset Against Collateral 0
Current liabilities: Fair value of hedging contracts [Member]
 
Offsetting Assets and Liabilities [Line Items]  
Derivative Liability, Fair Value, Gross Liability (1,373)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset 836
Derivative Liability, Fair Value, Amount Offset Against Collateral 537
Long-term liabilities: Fair value of hedging contracts [Member]
 
Offsetting Assets and Liabilities [Line Items]  
Derivative Liability, Fair Value, Gross Liability (617)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset 286
Derivative Liability, Fair Value, Amount Offset Against Collateral $ 331