Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Detail)

Contingencies - Additional Information (Detail) (USD $)
Sep. 30, 2013
Dec. 31, 2010
Commitment And Contingencies [Line Items]    
Number of pending claims 15  
Amount accrued $ 0  
Fine paid by for retention and use of individual agent in Nigeria with respect to customs-related issues 11,760,000  
Gulfco Site [Member]
Commitment And Contingencies [Line Items]    
Amount accrued $ 900,000  
Percent of costs to study and remediate site   20.00%