XML 74 R41.htm IDEA: XBRL DOCUMENT v2.4.0.6
Discontinued Operations - Additional Information (Detail) (USD $)
1 Months Ended 3 Months Ended 6 Months Ended 9 Months Ended 1 Months Ended
Mar. 31, 2011
Feb. 28, 2011
Sep. 30, 2012
Sep. 30, 2011
Jun. 30, 2012
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2011
Superior Refinery
Oct. 31, 2011
Meraux Refinery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                  
Proceeds from sales of assets           $ 388,000 $ 27,629,000 [1] $ 214,000,000 $ 325,000,000
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     $ 5,500,000 $ 14,500,000   $ 5,500,000 $ 14,500,000    
United Kingdom, supplemental tax rate for oil and gas companies 62.00% 50.00%              
[1] Reclassified to conform to current presentation.