Discontinued Operations - Additional Information (Detail) (USD $)	1 Months Ended			6 Months Ended		12 Months Ended
	Sep. 30, 2011 Property	Mar. 31, 2011	Feb. 28, 2011	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011		Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets						$ 569,000	$ 27,776,000	[1]	$ 2,189,000	[1]
Number of Refineries for disposal	2
Gain (loss) on disposal of refineries, net of tax	18,724,000
United Kingdom, corporation tax rate, tax relief on oil and gas decommissioning costs				50.00%	62.00%
United Kingdom, increase in tax expense of discontinued operations						5,523,000	14,461,000
United Kingdom, supplemental tax rate for oil and gas companies		62.00%	50.00%
Superior Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets	214,000,000
Gain (loss) on disposal of refineries, net of tax	77,585,000
Meraux Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets	325,000,000
Gain (loss) on disposal of refineries, net of tax	58,861,000
Gain (loss) on liquidation of inventories	$ 179,152,000

[1] Reclassified to conform to current presentation.