Quarterly report pursuant to Section 13 or 15(d)

General - Additional Information (Detail)

v3.5.0.2
General - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2016
Dec. 31, 2015
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Revenue, Major Customer [Line Items]          
Payments to Acquire Property, Plant, and Equipment       $ 16,257 $ 54,605
Percentage accounted for under the equity method 50.00%     50.00%  
Reimbursable Costs $ 18,900   $ 27,800 $ 37,900 $ 47,500
Deposits in domestic bank 69,100 $ 91,300   69,100  
Deposits, Foreign $ 41,700 44,100   $ 41,700  
Noncontrolling Interest, Fair Value Disclosure   6,750      
Redeemable Noncontrolling Interest, Equity, Carrying Amount   3,000      
Exxon Neftegas Limited [Member]          
Revenue, Major Customer [Line Items]          
Percentage of revenue from major customer       39.80% 26.00%
Reimbursement Revenue       $ 36,900 $ 39,700
Concentration Risk, Other Risk       0.287 0.181
BP Exploration Alaska, Inc. [Member]          
Revenue, Major Customer [Line Items]          
Percentage of revenue from major customer       11.90%  
ITS Arabia Limited [Member]          
Revenue, Major Customer [Line Items]          
Purchase Price of Remaining Noncontrolling Interest   $ 3,400