Annual report pursuant to Section 13 and 15(d)

Contingencies - Additional Information (Details)

v3.3.1.900
Contingencies - Additional Information (Details)
 1 Months Ended 3 Months Ended 12 Months Ended
Jan. 31, 2014
USD ($)
Mar. 31, 2014
USD ($)
Dec. 31, 2015
USD ($)
claim
Dec. 31, 2014
USD ($)
Dec. 15, 2014
USD ($)
Dec. 31, 2010
USD ($)
Loss Contingencies [Line Items]            
Underpayment of royalties $ 30,000          
Under payment percentage of total royalty payments 0.0045%          
Statutory fine payment relative to underpayment   $ 2,300,000        
Statutory fine payment relative to underpayment revised value   $ 1,100,000        
Amount accrued     $ 0 $ 0    
Loss contingency, range of possible loss, minimum         $ 0  
Loss contingency, range of possible loss, maximum         $ 32,000,000  
Insurance claims submitted for removal-of-wreck expenses     $ 43,000,000      
Notified disallowed amount in reductions taken by ONRR           $ 4,700,000
Number of notices received | claim     4      
Unpaid proposed penalties     $ 1,000,000      
BSEE            
Loss Contingencies [Line Items]            
Number of notices received | claim     3      
Proposed civil penalties paid     $ 200,000      
Unpaid proposed penalties     8,100,000      
Liberty Mutual Insurance Co            
Loss Contingencies [Line Items]            
Insurance claims received     5,000,000      
Revised estimate            
Loss Contingencies [Line Items]            
Insurance claims receivable     31,000,000      
Comprehensive General Liability policy            
Loss Contingencies [Line Items]            
Insurance claims received     1,000,000      
Energy Package            
Loss Contingencies [Line Items]            
Insurance claims received     1,000,000      
Starr Marine            
Loss Contingencies [Line Items]            
Insurance claims received     $ 5,000,000