Quarterly report pursuant to Section 13 or 15(d)

Commitments And Contingencies (Narrative) (Details)

v3.8.0.1
Commitments And Contingencies (Narrative) (Details)
$ in Thousands
 9 Months Ended
Sep. 30, 2017
USD ($)
item
Dec. 31, 2016
USD ($)
Jun. 30, 2016
USD ($)
Commitments And Contingencies [Line Items]      
Number Monthly Payments | item 7    
Contractual Obligation Company Share     $ 5,100
Abandonment Funding $ 8,510 $ 8,510  
Abandonment cost related to annual funding 61,100    
Abandonment cost related to annual funding, net 19,000    
Accrued potential fees from customs audit 1,000    
Gabon [Member]      
Commitments And Contingencies [Line Items]      
Abandonment Funding 8,500    
Abandonment funding, gross $ 27,400    
Accrued Payroll Taxes   $ 1,000  
Offshore Gabon [Member]      
Commitments And Contingencies [Line Items]      
Production License Agreement Term Extended By Government 5 years    
Percentage of annual funding over seven years 12.14%    
Funding period for initial rate 7 years    
Second funding period of production license 3 years    
Percentage of annual funding over last three years 5.00%    
Funding period abandonment funding 10 years    
Number of contract extension periods | item 2