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Derivative Instruments (Details) (Forward Contracts [Member], USD $) | Jun. 30, 2012 gal
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Sales [Member] |
Outstanding trading contracts |
Quantity in Gallons | 5,754,000
Weighted Average Contract Prices | $ 0.8933
Sales [Member] | Maximum [Member] |
Outstanding trading contracts |
Estimated Market Prices | $ 1.3775
Sales [Member] | Minimum [Member] |
Outstanding trading contracts |
Estimated Market Prices | $ 0.7200
Purchase [Member] |
Outstanding trading contracts |
Quantity in Gallons | 5,670,000
Weighted Average Contract Prices | $ 0.8724
Purchase [Member] | Maximum [Member] |
Outstanding trading contracts |
Estimated Market Prices | $ 1.3300
Purchase [Member] | Minimum [Member] |
Outstanding trading contracts |
Estimated Market Prices | $ 0.6825

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- Details
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