v2.4.0.6
Revolving Credit Facility - Additional Information (Detail) (USD $)
12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 1 Months Ended
Dec. 31, 2012
Ratio
Dec. 31, 2011
Dec. 31, 2012
Covenants agreements one [Member]
Dec. 31, 2012
Covenants agreements two [Member]
Nov. 16, 2012
Minimum [Member]
Dec. 31, 2012
Minimum [Member]
Interest rate calculation one [Member]
Dec. 31, 2012
Minimum [Member]
Interest rate calculation two [Member]
Nov. 16, 2012
Maximum [Member]
Dec. 31, 2012
Maximum [Member]
Interest rate calculation one [Member]
Dec. 31, 2012
Maximum [Member]
Interest rate calculation two [Member]
Oct. 11, 2012
Current maximum [Member]
Apr. 26, 2012
Current maximum [Member]
Sep. 07, 2012
Current maximum [Member]
Thirteenth amendment credit agreement [Member]
Thirty six month derivatives contracts [Member]
Sep. 07, 2012
Current maximum [Member]
Thirteenth amendment credit agreement [Member]
Sixty month derivatives contracts [Member]
Oct. 11, 2012
Previous maximum [Member]
Apr. 26, 2012
Previous maximum [Member]
Sep. 07, 2012
Previous maximum [Member]
Thirteenth amendment credit agreement [Member]
Thirty six month derivatives contracts [Member]
Line of Credit Facility [Line Items]                                  
Maximum borrowing revolving credit facility $ 300,000,000                                
Revolving credit facility, borrowing base 280,000,000                           270,000,000    
Maturity period of revolving credit facility Jul. 31, 2014                                
Revolving credit facility, interest rate description Borrowings bear interest based on the agent bank's prime rate plus an applicable margin ranging from 0.75% to 1.75%, or the sum of the Eurodollar rate plus an applicable margin ranging from 1.75% to 2.75%.                                
Revolving credit facility, marginal percentage           0.75% 1.75%   1.75% 2.75%              
Annual commitment fee of unused borrowings 0.50%                                
Borrowing base                       270,000,000       260,000,000  
Projected production under credit agreement                         100.00% 85.00%     85.00%
Issuance of unsecured senior notes         200,000,000     400,000,000                  
Increase in the borrowing base for line of credit facility                     280,000,000            
Amount outstanding under revolving credit facility 106,000,000 43,800,000                              
Interest rate applicable to revolving credit facility 2.70% 3.70%                              
Unused letters of credit outstanding 325,000                                
Consolidated current assets ratio 1.0                                
Consolidated current liabilities ratio 1.0                                
Covenant description     A consolidated modified current ratio covenant that requires us to maintain a ratio of not less than 1.0 to 1.0 at all times                            
Consolidated funded debt ratio 4.0                                
Consolidated earnings before interest taxes depreciation amortization and exploration expenses ratio 1.0                                
Ratio covenant description       A consolidated funded debt to consolidated EBITDAX ratio covenant that requires us to maintain a ratio of not more than 4.0 to 1.0 at the end of each fiscal quarter                          
Debt default description In addition, our credit agreement contains customary events of default that would permit our lenders to accelerate the debt under our credit agreement if not cured within applicable grace periods, including, among others, failure to make payments of principal or interest when due, materially incorrect representations and warranties, failure to make mandatory prepayments in the event of borrowing base deficiencies, breach of covenants, defaults upon other obligations in excess of $500,000, events of bankruptcy, the occurrence of one or more unstayed judgments in excess of $500,000 not covered by an acceptable policy of insurance, failure to pay any obligation in excess of $500,000 owed under any derivatives transaction or in any amount if the obligation under the derivatives transaction is secured by collateral under the credit agreement, any event of default by the Company occurs under any agreement entered into in connection with a derivatives transaction, liens securing the loans under the credit agreement cease to be in place, a Change in Control (as defined in the credit agreement) of the Company occurs, and dissolution of the Company.                                
Debt default amount $ 500,000