Quarterly report pursuant to Section 13 or 15(d)

Reportable Segments - Additional Information (Detail)

v2.4.0.8
Reportable Segments - Additional Information (Detail)
3 Months Ended 6 Months Ended 12 Months Ended 3 Months Ended 6 Months Ended
Jun. 30, 2012
customer
Jun. 30, 2013
segment
Dec. 31, 2012
segment
Jun. 30, 2013
International Drilling [Member]
Jun. 30, 2013
Exxon Neftegas Limited [Member]
Jun. 30, 2013
Exxon Neftegas Limited [Member]
Segment Information [Line Items]            
Number of operating segments   5 6      
Percentage of revenue from major customer       37.70% 13.90% 14.30%
Number of customers accounted for more than 10 percent or more of revenues 0