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Significant Concentrations (Schedule Of Purchasers Accounted More Than Ten Percent Of Total Sales) (Details)	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Texon L.P. [Member]
Significant Concentrations [Line Items]
Percentage of sales to total sales	18.00%		19.00%		30.00%
Plains All American Pipeline L.P. [Member]
Significant Concentrations [Line Items]
Percentage of sales to total sales	16.00%		28.00%			[1]
Enserco Energy Inc. [Member]
Significant Concentrations [Line Items]
Percentage of sales to total sales	15.00%			[1]		[1]
Whiting Petroleum Corporation [Member]
Significant Concentrations [Line Items]
Percentage of sales to total sales		[1]	11.00%			[1]
Tesoro Refining And Marketing Company [Member]
Significant Concentrations [Line Items]
Percentage of sales to total sales		[1]		[1]	32.00%
[1] N/A Not applicable as the sales to these purchasers did not account for more than 10% of the Company's total sales for such respective periods.

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- Details

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- Definition

The percentage of net product revenue to total net revenue from the sale of goods as of year end.

+ References

No definition available.

+ Details

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