Discontinued Operations -Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Sep. 30, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets		$ 27,629,000	$ 2,195,000	[1]
Number of Refineries for disposal	2
Gain (loss) on disposal of refineries, net of tax	16,900,000
Superior, Wisconsin Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets	214,000,000
Meraux, Louisiana Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets	325,000,000
Superior Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of refineries, net of tax	91,100,000
Meraux Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of refineries, net of tax	$ (74,200,000)

[1] Reclassified to conform to current presentation