Quarterly report pursuant to Section 13 or 15(d)

Reportable Segments - Additional Information (Detail)

v3.3.0.814
Reportable Segments - Additional Information (Detail)
9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Segment Information [Line Items]    
Number of Reportable Segments 2  
Exxon Neftegas Limited [Member]    
Segment Information [Line Items]    
Percentage of revenue from major customer 27.00% 18.90%
Exxon Neftegas Limited [Member] | International & Alaska Drilling [Member]    
Segment Information [Line Items]    
Percentage of revenue from major customer 44.70% 39.90%