Quarterly report pursuant to Section 13 or 15(d)

Acquisitions And Dispositions (Narrative) (Details)

v3.7.0.1
Acquisitions And Dispositions (Narrative) (Details)
a in Millions
 1 Months Ended 3 Months Ended
Nov. 22, 2016
Mar. 14, 2016
USD ($)
Jan. 01, 2014
Oct. 31, 2014
item
Apr. 30, 2014
USD ($)
Nov. 30, 2006
USD ($)
a
item
Jun. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Oct. 17, 2016
USD ($)
Business Acquisition [Line Items]                    
Fair value of fields               $ 10,000,000 $ 10,000,000  
Allowance for accounts with partners               $ 500,000 500,000  
Offshore Gabon [Member]                    
Business Acquisition [Line Items]                    
Production license agreement term extended by government               5 years    
Scenario, Forecast [Member]                    
Business Acquisition [Line Items]                    
Gain from sale of property             $ 300,000      
East Poplar Dome Field [Member]                    
Business Acquisition [Line Items]                    
Fair value of fields                   $ 250,000
Joint Operating With Republic Of Angola [Member]                    
Business Acquisition [Line Items]                    
Production license agreement term           4 years        
Production license agreement term extended by government           3 years        
Area under acquire property exploration rights agreement term (acres) | a           1.4        
Number of exploration wells | item           2        
Number Of Additional Exploration Wells | item       2            
Joint operation agreement related to third party in working interest percentage           40.00%        
Additional joint operation agreement related to third party in working interest percentage           10.00%        
Stipulated payment for each exploration well, under PSA terms           $ 10,000,000        
Drilling commitment, net           $ 5,000,000        
Liability for the penalty               $ 15,000,000 $ 15,000,000  
Write off of bad debt         $ 7,600,000          
Working interest ownership other, percentage     40.00%              
Etame [Member]                    
Business Acquisition [Line Items]                    
Percentage of working interest 2.98%                  
Percentage of participating interest 3.23%                  
Sonangol P&P [Member]                    
Business Acquisition [Line Items]                    
Payment from joint venture partners   $ 19,000,000                
Write off of bad debt   7,600,000                
Interest income   $ 3,200,000