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
 3 Months Ended
Mar. 31, 2018
USD ($)
item
Dec. 31, 2017
USD ($)
Commitments And Contingencies [Line Items]    
Abandonment Funding $ 10,808 $ 10,808
Abandonment cost related to annual funding 61,100  
Abandonment cost related to annual funding, net 19,000  
Accrued liabilities and other 13,477 12,991
Potential Fees From Customs Audits [Member]    
Commitments And Contingencies [Line Items]    
Accrued liabilities and other 1,300 1,300
Gabon [Member]    
Commitments And Contingencies [Line Items]    
Abandonment Funding 10,800  
Abandonment funding, gross 34,800  
Accrued estimated settlement $ 400 500
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  
FPSO Charter [Member]    
Commitments And Contingencies [Line Items]    
Number of extensions | item 2  
Period of charter (in years) 1 year  
Percentage of share in charter payment 31.10%  
Share in charter payment, approximate annual amount $ 9,700  
Liabilities, guarantees' fair value 500 500
Contractual obligation $ 77,500 $ 85,200