Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Details)

v3.3.0.814
Contingencies - Additional Information (Details) - USD ($)
 1 Months Ended 3 Months Ended
Jan. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Dec. 15, 2014
Dec. 31, 2010
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    
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   $ 42,000,000      
Notified disallowed amount in reductions taken by ONRR         $ 4,700,000
Liberty Mutual Insurance Co          
Loss Contingencies [Line Items]          
Insurance claims received   5,000,000      
Revised estimate          
Loss Contingencies [Line Items]          
Insurance claims receivable   30,000,000      
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