Quarterly report pursuant to Section 13 or 15(d)

Reportable Segments - Additional Information (Detail)

v2.4.0.6
Reportable Segments - Additional Information (Detail)
3 Months Ended 12 Months Ended
Mar. 31, 2013
Segment
Mar. 31, 2012
Customer
Dec. 31, 2012
Segment
Segment Information [Line Items]      
Number of operating segments 5   6
Number of customers accounted for more than 10 percent or more of revenues   0  
International Drilling [Member]
     
Segment Information [Line Items]      
Percentage of revenue from major customer 38.50%    
Exxon Neftegas Limited [Member]
     
Segment Information [Line Items]      
Percentage of revenue from major customer 15.10%