Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Details)

v3.8.0.1
Contingencies - Additional Information (Details)
 3 Months Ended 9 Months Ended
Jan. 27, 2017
USD ($)
Oct. 28, 2016
USD ($)
Dec. 15, 2014
USD ($)
DeepwaterWell
Sep. 30, 2017
USD ($)
Order
Sep. 30, 2017
USD ($)
claim
Jun. 30, 2017
USD ($)
May 31, 2017
USD ($)
Dec. 31, 2010
USD ($)
Loss Contingencies [Line Items]                
Outstanding obligation to secure financial assurances upon rescindment         $ 0      
Number of supplemental bonding orders rescinded | Order       4        
Additional supplemental bonding       $ 260,800,000 260,800,000      
Number of deepwater wells abandoned | DeepwaterWell     3          
Deposit Into registry of court       49,500,000 49,500,000      
Loss contingency accrued amount       49,500,000 $ 49,500,000      
Notified disallowed amount in reductions taken by ONRR               $ 4,700,000
Payments for royalty $ 4,700,000              
Royalty payment processing revised period         84 months      
Additional royalty payment         $ 1,200,000      
BSEE                
Loss Contingencies [Line Items]                
Loss contingency accrued amount       3,400,000 $ 3,400,000      
Number of notices | claim         6      
Proposed civil penalties related to various incidents of noncompliance, total         $ 7,400,000      
Payments for civil penalty         100,000      
Increase in estimated liability         1,900,000      
Apache Corporation                
Loss Contingencies [Line Items]                
Deposit Into registry of court       49,500,000 49,500,000      
Apache Corporation | Judicial Ruling                
Loss Contingencies [Line Items]                
Amount owed to Apache under judicial decision             $ 43,200,000  
Prejudgment interest, attorney fees and judgment costs             $ 6,300,000  
Amount awarded for non-compliance fines and lawsuits   $ 43,200,000 $ 24,900,000          
Amount offset against litigation compensation amount   $ 17,000,000            
Apache Corporation | Judicial Ruling | Other Income/Expense                
Loss Contingencies [Line Items]                
Recognized prejudgment interest, attorney fees and judgment costs.         6,300,000      
Apache Corporation | Judicial Ruling | Asset Retirement Obligation                
Loss Contingencies [Line Items]                
Capitalized loss contingency damages payable to other party except attorney fees judgment costs and prejudgment interest       43,200,000 43,200,000      
Apache Corporation | Judicial Ruling | Other Noncurrent Assets                
Loss Contingencies [Line Items]                
Deposit Into registry of court           $ 49,500,000    
Apache Corporation | Judicial Ruling | Other Noncurrent Liabilities                
Loss Contingencies [Line Items]                
Loss contingency accrued amount       $ 49,500,000 $ 49,500,000