Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Narrative) (Details)

v3.3.1.900
Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Dec. 31, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Accounting Policies [Line Items]            
Write-down of oil and natural gas properties $ 121,134 $ 87,301   $ 208,435    
Capitalized interest       10,459 $ 4,295 $ 4,410
Amortization of financing costs       3,123 1,272 471
Deferred financing costs, net of accumulated amortization 11,435     11,435 13,424  
Deferred financing costs 3,642     3,642 4,776  
Deferred tax assets, valuation allowance 108,843     108,843    
Interest paid       28,437 7,283 13,189
Other Property and Equipment [Member]            
Accounting Policies [Line Items]            
Depreciation       865 836 $ 750
Accumulated depreciation $ 14,719     $ 14,719 $ 14,005  
Other Property and Equipment [Member] | Minimum [Member]            
Accounting Policies [Line Items]            
Useful life       3 years    
Other Property and Equipment [Member] | Maximum [Member]            
Accounting Policies [Line Items]            
Useful life       20 years    
Medusa Spar, LLC [Member]            
Accounting Policies [Line Items]            
Divestiture of business, percentage of business sold     10.00%      
Ownership percentage of production facilities     75.00%     75.00%
Medusa Field [Member]            
Accounting Policies [Line Items]            
Divestiture of business, percentage of business sold     15.00%      
Stock options [Member]            
Accounting Policies [Line Items]            
Vesting period       3 years    
RSU RSU equity awards [Member]            
Accounting Policies [Line Items]            
Vesting period       3 years    
Cash-settleable RSU awards [Member]            
Accounting Policies [Line Items]            
Vesting period       3 years