Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies - Additional Information (Details)

v3.3.1.900
Significant Accounting Policies - Additional Information (Details)
 2 Months Ended 3 Months Ended 12 Months Ended 24 Months Ended
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2015
USD ($)
$ / bbl
$ / BTU
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Dec. 31, 2015
USD ($)
Feb. 26, 2016
USD ($)
May. 31, 2015
Significant Accounting Policies [Line Items]                      
Other assets   $ 5,462,000       $ 5,462,000 $ 9,307,000   $ 5,462,000    
Other liabilities   16,178,000       16,178,000 13,691,000   16,178,000    
Deferred income taxes             175,326,000        
Net cash provided by operating activities           132,554,000 473,973,000 $ 562,708,000      
Net cash used in investing activities           86,075,000 (592,502,000) (616,155,000)      
Natural gas imbalances   6,900,000       6,900,000 6,400,000   6,900,000    
Allowance for doubtful accounts receivable   2,500,000       $ 2,500,000 700,000   2,500,000    
Usage of the amounts recorded for allowance for doubtful accounts             0   $ 0    
Percentage of discount from proved reserves           10.00%          
Ceiling test write-down of oil and natural gas properties   $ 32,400,000 $ 441,600,000 $ 252,800,000 $ 260,400,000 $ 987,238,000 0 0      
Proved undeveloped reserves classification period to be drilled           5 years          
Goodwill, acquired during period             0 0      
Write-offs of debt issuance costs           $ 3,200,000          
Net proceeds received in conjunction with a payment for an option exercised               9,100,000      
SEC Methodology | Natural Gas                      
Significant Accounting Policies [Line Items]                      
Price using SEC methodology | $ / BTU           2.59          
SEC Methodology | Crude Oil Per Barrel                      
Significant Accounting Policies [Line Items]                      
Price using SEC methodology | $ / bbl           46.79          
Fixtures and Non-Oil and Natural Gas Property and Equipment | Minimum                      
Significant Accounting Policies [Line Items]                      
Estimated useful lives           5 years          
Fixtures and Non-Oil and Natural Gas Property and Equipment | Maximum                      
Significant Accounting Policies [Line Items]                      
Estimated useful lives           7 years          
Subsequent Event                      
Significant Accounting Policies [Line Items]                      
Amount borrowed under Credit Agreement                   $ 340,000,000  
Obligation to secure financial assurances $ 260,800,000                    
9.00% Term Loan due 2020                      
Significant Accounting Policies [Line Items]                      
Debt instrument interest rate   9.00%       9.00%     9.00%   9.00%
Accounting Standards Update 2015-17                      
Significant Accounting Policies [Line Items]                      
Deferred income taxes             11,700,000        
Restatement Adjustment                      
Significant Accounting Policies [Line Items]                      
Other assets             (7,900,000)        
Other liabilities             (7,900,000)        
Net cash provided by operating activities             (37,500,000) 1,400,000      
Net cash used in investing activities             $ (37,500,000) $ 1,400,000