v3.5.0.2
Long-Term Debt - Additional Information (Detail)
 1 Months Ended 3 Months Ended 9 Months Ended
May 03, 2016
USD ($)
Dec. 31, 2015
USD ($)
Aug. 31, 2015
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2015
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2015
USD ($)
Mar. 31, 2016
USD ($)
Jun. 30, 2013
USD ($)
Line of Credit Facility [Line Items]                  
Senior secured credit facility   $ 273,000,000   $ 275,000,000   $ 275,000,000      
Debt issuance costs written off           563,000      
Senior notes, net   225,839,000   226,450,000   226,450,000      
Gain on extinguishment of debt         $ 1,483,000   $ 1,483,000    
Senior Notes [Member]                  
Line of Credit Facility [Line Items]                  
Debt issuance costs   4,481,000   3,870,000   3,870,000      
Senior notes, net   225,839,000   226,450,000   226,450,000      
Principal amount of senior notes outstanding   230,320,000   $ 230,320,000   $ 230,320,000      
7% Senior Notes Originated June 11, 2013 [Member] | Senior Notes [Member]                  
Line of Credit Facility [Line Items]                  
Senior notes, net                 $ 250,000,000
Stated interest rate       7.00%   7.00%      
Debt instrument payment of interest           Semi-annually on June 15 and December 15.      
Repurchased senior notes face value   14,700,000 $ 5,000,000            
Repurchased price of senior notes     $ 3,500,000            
Gain on extinguishment of debt         $ 1,500,000        
Gain on repurchase of senior notes   9,100,000              
Principal amount of senior notes outstanding       $ 230,300,000   $ 230,300,000      
Senior Secured Credit Facility [Member]                  
Line of Credit Facility [Line Items]                  
Senior secured credit facility, borrowing base $ 325,000,000     325,000,000   325,000,000   $ 450,000,000  
Senior secured facility, maximum borrowing capacity       1,000,000,000   $ 1,000,000,000      
Maturity period of senior secured credit facility           May 07, 2019      
Annual commitment fee of unused borrowings           0.50%      
Senior secured credit facility, interest rate description           Borrowings under the Credit Facility bore interest based on the agent bank's prime rate plus an applicable margin ranging from 1.50% to 2.50%, or the sum of the LIBOR rate plus an applicable margin ranging from 2.50% to 3.50%. In addition, we pay an annual commitment fee of 0.50% of unused borrowings available.      
Senior secured credit facility   273,000,000   $ 275,000,000   $ 275,000,000      
Interest rate applicable of senior secured credit facility       3.80%          
Unused letters of credit outstanding   300,000   $ 300,000   $ 300,000      
Production from liens covering the oil and gas properties           90.00%      
Interest coverage ratio, through December 31, 2018 1.5                
Interest coverage ratio, thereafter 2.0                
Increase in applicable margin rates on borrowings 1.00%                
Second lien indebtedness $ 150,000,000                
Cash and cash equivalents, minimum threshold to reduce outstanding borrowings under credit facility 35,000,000                
Debt issuance costs written off 600,000                
Debt issuance costs $ 200,000 $ 2,252,000   $ 1,439,000   $ 1,439,000      
Outstanding equity interests ownership percentage       50.00%   50.00%      
Senior Secured Credit Facility [Member] | Covenants Agreements One [Member]                  
Line of Credit Facility [Line Items]                  
Covenant description            a consolidated interest coverage ratio covenant (as defined in the Credit Facility) that requires us to maintain a ratio of consolidated EBITDAX to cash Interest Expense (as defined in the Credit Facility) as of the last day of any fiscal quarter of not less than 1.25 to 1.0 (or 1.0 to 1.0 following the issuance of second lien indebtedness) through December 31, 2017, a ratio of not less than 1.5 to 1.0 through December 31, 2018, and a ratio of not less than 2.0 to 1.0 thereafter, and  a consolidated modified current ratio covenant (as defined in the Credit Facility) that requires us to maintain a ratio of not less than 1.0 to 1.0 as of the last day of any fiscal quarter.      
Senior Secured Credit Facility [Member] | Before Second Lien Indebtedness [Member]                  
Line of Credit Facility [Line Items]                  
Interest coverage ratio, through December 31, 2017 1.25                
Senior Secured Credit Facility [Member] | Before Second Lien Indebtedness [Member] | Covenants Agreements One [Member]                  
Line of Credit Facility [Line Items]                  
Minimum current ratio           1.25      
Senior Secured Credit Facility [Member] | After Second Lien Indebtedness [Member]                  
Line of Credit Facility [Line Items]                  
Interest coverage ratio, through December 31, 2017 1.0                
Senior Secured Credit Facility [Member] | After Second Lien Indebtedness [Member] | Covenants Agreements One [Member]                  
Line of Credit Facility [Line Items]                  
Minimum current ratio           1.0      
Senior Secured Credit Facility [Member] | Minimum [Member] | Prime Rate [Member]                  
Line of Credit Facility [Line Items]                  
Senior secured credit facility, marginal percentage           1.50%      
Senior Secured Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]                  
Line of Credit Facility [Line Items]                  
Senior secured credit facility, marginal percentage           2.50%      
Senior Secured Credit Facility [Member] | Maximum [Member] | Prime Rate [Member]                  
Line of Credit Facility [Line Items]                  
Senior secured credit facility, marginal percentage           2.50%      
Senior Secured Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]                  
Line of Credit Facility [Line Items]                  
Senior secured credit facility, marginal percentage           3.50%