Discontinued Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011		Sep. 30, 2011 Superior Refinery	Sep. 30, 2011 Meraux Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of assets	$ 123	$ 76	[1]	$ 214,000	$ 325,000

[1] Reclassified to conform to current presentation.