Quarterly report pursuant to Section 13 or 15(d)

Reportable Segments - Additional Information (Detail)

v3.2.0.727
Reportable Segments - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Segment Information [Line Items]      
Number of Reportable Segments   2  
Change in fair value of derivative positions $ (479)    
Exxon Neftegas Limited [Member]      
Segment Information [Line Items]      
Percentage of revenue from major customer   26.00% 17.90%
Exxon Neftegas Limited [Member] | International & Alaska Drilling [Member]      
Segment Information [Line Items]      
Percentage of revenue from major customer   44.30% 37.10%