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)
 12 Months Ended 132 Months Ended
Dec. 31, 2015
USD ($)
Mcf / bbl
purchaser
shares
Dec. 31, 2014
USD ($)
shares
Dec. 31, 2013
USD ($)
shares
Dec. 31, 2015
USD ($)
shares
Summary Of Significant Accounting Policies [Line Items]        
Accounts receivable, collection period 30 days      
Allowance for Doubtful Accounts Receivable $ 0 $ 0   $ 0
Impairment of oil and gas properties $ 1,440,418,000 0 $ 0  
Conversion ratio, gas to barrels of oil | Mcf / bbl 6      
Capitalized costs of oil and natural gas properties excluded from amortization $ 1,817,701,000 1,465,538,000   1,817,701,000
Unrecognized tax benefits that would impact effective tax rate 0     0
Income tax examination, penalties and interest expense 0      
Carrying Value 242,393,000 369,581,000   242,393,000
Oil and gas reclamation liability, noncurrent $ 0 $ 0   $ 0
Investment owned, balance, shares | shares 0     0
Granted for purchase of previous Plan's common stock (shares) | shares 0 0 0 0
Employee Stock Option        
Summary Of Significant Accounting Policies [Line Items]        
Vesting period, contractual term 10 years      
Investment in Tatex Thailand III, LLC        
Summary Of Significant Accounting Policies [Line Items]        
Carrying Value $ 0 $ 0   $ 0
Equity method investment, other than temporary impairment   12,100,000    
Investment in Grizzly Oil Sands ULC        
Summary Of Significant Accounting Policies [Line Items]        
Carrying Value 50,645,000 180,218,000   50,645,000
Equity method investment, other than temporary impairment $ 101,600,000      
Minimum        
Summary Of Significant Accounting Policies [Line Items]        
Useful life 3 years      
Minimum | Employee Stock Option        
Summary Of Significant Accounting Policies [Line Items]        
Vesting period 3 years      
Minimum | Restricted Stock        
Summary Of Significant Accounting Policies [Line Items]        
Vesting period 2 years      
Maximum        
Summary Of Significant Accounting Policies [Line Items]        
Useful life 30 years      
Maximum | Employee Stock Option        
Summary Of Significant Accounting Policies [Line Items]        
Vesting period 5 years      
Maximum | Restricted Stock        
Summary Of Significant Accounting Policies [Line Items]        
Vesting period 5 years      
Customer Concentration Risk | Accounts Receivable        
Summary Of Significant Accounting Policies [Line Items]        
Concentration risk, number of purchasers | purchaser 3      
New Accounting Pronouncement, Early Adoption, Effect | Long-term Debt        
Summary Of Significant Accounting Policies [Line Items]        
Deferred finance costs $ 17,900,000 12,900,000   17,900,000
New Accounting Pronouncement, Early Adoption, Effect | Other Assets        
Summary Of Significant Accounting Policies [Line Items]        
Deferred finance costs $ 17,900,000 $ 12,900,000   $ 17,900,000