Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Detail)

Contingencies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Jun. 30, 2013
Dec. 31, 2012
Commitment And Contingencies [Line Items]    
Number of Lawsuits 15  
Amount accrued $ 0  
Percent of costs to study and remediate site 20.00%  
Fine paid by for retention and use of individual agent in Nigeria with respect to customs-related issues 11.76  
Payment of disgorgement 3.05  
Prejudgment interest 1.04  
Prejudgment interest and disgorgement amount paid 4.09  
Legal settlement expense   15.85
Gulfco Site [Member]
Commitment And Contingencies [Line Items]    
Amount accrued $ 0.7