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Long-Term Debt (Narrative) (Details) (USD $) |  |  |  |  |  |  |  |  | 6 Months Ended | 1 Months Ended | 6 Months Ended
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Jun. 30, 2012 | May 02, 2012 | Dec. 31, 2011 | Oct. 31, 2011 | May 03, 2011 | Dec. 24, 2010 Bank Of Nova Scotia [Member] | Sep. 30, 2010 Bank Of Nova Scotia [Member] | Jun. 30, 2012 Federal Funds Rate [Member] | Jun. 30, 2012 One-Month Euro Dollar Rate [Member] | Jun. 30, 2012 Maximum [Member] | Jun. 30, 2012 Maximum [Member] Base Rate [Member] Base Rate Loans [Member] | Jun. 30, 2012 Maximum [Member] Base Rate [Member] Eurodollar Loans [Member] | Jun. 30, 2012 Minimum [Member] | Jun. 30, 2012 Minimum [Member] Base Rate [Member] Base Rate Loans [Member] | Jun. 30, 2012 Minimum [Member] Base Rate [Member] Eurodollar Loans [Member] | Mar. 31, 2011 Building Loan [Member] | Jun. 30, 2012 Building Loan [Member]
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revolving credit facility |  |  |  |  |  |  | $ 350,000,000 |  | $ 100,000,000 |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  |  | 155,000,000 |  |  | 125,000,000 | 90,000,000 | 65,000,000 | 50,000,000 |  |  |  |  |  |  |  |  |  |
Company's borrowings, outstanding principal amount | 68,000,000 | [1] |  |  | [1] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loan, periodic monthly payment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 22,000
Building loan, outstanding amount of building loan refinanced |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,400,000 |
Stated interest rate, per annum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.82% |
Debt instrument, base interest rate before basis spread or other rate adjustments, percent |  |  |  |  |  |  |  |  |  |  |  |  | 1.75% | 2.75% |  | 1.00% | 2.00% |  |
Debt instrument, basis spread on variable rate |  |  |  |  |  |  |  |  |  | 0.50% | 1.00% |  |  |  |  |  |  |  |
Line of Credit Facility, Interest Rate During Period |  |  |  |  |  |  |  |  |  |  | 2.49% |  |  |  |  |  |  |  |
Ratio of funded debt to EBITDAX necessary to maintain covenants |  |  |  |  |  |  |  |  |  |  |  | 2.00 |  |  |  |  |  |  |
Ratio of EBITDAX to interest expense necessary to maintain covenants |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.00 |  |  |  |
[1] | On September 30, 2010, the Company entered into a $100.0 million senior secured revolving credit agreement with The Bank of Nova Scotia, as administrative agent and letter of credit issuer and lead arranger, and Amegy Bank National Association. The revolving credit facility initially matured on September 30, 2013 and had an initial borrowing base availability of $50.0 million, which was increased to $65.0 million effective December 24, 2010. The credit agreement is secured by substantially all of the Company’s assets. The Company’s wholly-owned subsidiaries guaranteed the obligations of the Company under the credit agreement.On May 3, 2011, the Company entered into a first amendment to the revolving credit agreement with The Bank of Nova Scotia, Amegy Bank, Key Bank National Association (“Key Bank”) and Société Générale. Pursuant to the terms of the first amendment, Key Bank and Société Générale were added as additional lenders, the maximum amount of the facility was increased to $350.0 million, the borrowing base was increased to $90.0 million, certain fees and rates payable by the Company under the credit agreement were decreased, and the maturity date was extended until May 3, 2015. On October 31, 2011, the Company entered into additional amendments to its revolving credit facility pursuant to which, among other things, the borrowing base under this facility was increased to $125.0 million. Effective May 2, 2012, the Company entered into additional amendments to its revolving credit facility pursuant to which, among other things, the borrowing base was increased to $155.0 million and Credit Suisse, Deutsche Bank Trust Company Americas and Iberiabank were added as additional lenders and Société Générale left the bank group. As of June 30, 2012, approximately $68,000,000 was outstanding under the credit agreement.Advances under the credit agreement, as amended, may be in the form of either base rate loans or eurodollar loans. The interest rate for base rate loans is equal to (1) the applicable rate, which ranges from 1.00% to 1.75%, plus (2) the highest of: (a) the federal funds rate plus 0.5%, (b) the rate of interest in effect for such day as publicly announced from time to time by agent as its “prime rate,” and (c) the eurodollar rate for an interest period of one month plus 1.00%. The interest rate for eurodollar loans is equal to (1) the applicable rate, which ranges from 2.00% to 2.75%, plus (2) the London interbank offered rate that appears on Reuters Screen LIBOR01 Page for deposits in U.S. dollars, or, if such rate is not available, the offered rate on such other page or service that displays the average British Bankers Association Interest Settlement Rate for deposits in U.S. dollars, or, if such rate is not available, the average quotations for three major New York money center banks of whom the agent shall inquire as the “London Interbank Offered Rate” for deposits in U.S. dollars. At June 30, 2012, amounts borrowed under the credit agreement bore interest at the eurodollar rate (2.49%).The credit agreement contains customary negative covenants including, but not limited to, restrictions on the Company’s and its subsidiaries’ ability to: incur indebtedness; grant liens; pay dividends and make other restricted payments; make investments; make fundamental changes; enter into swap contracts and forward sales contracts; dispose of assets; change the nature of their business; and enter into transactions with their affiliates. The negative covenants are subject to certain exceptions as specified in the credit agreement. The credit agreement also contains certain affirmative covenants, including, but not limited to the following financial covenants: (1) the ratio of funded debt to EBITDAX (net income, excluding any non-cash revenue or expense associated with swap contracts resulting from ASC 815, plus without duplication and to the extent deducted from revenues in determining net income, the sum of (a) the aggregate amount of consolidated interest expense for such period, (b) the aggregate amount of income, franchise, capital or similar tax expense (other than ad valorem taxes) for such period, (c) all amounts attributable to depletion, depreciation, amortization and asset or goodwill impairment or writedown for such period, (d) all other non-cash charges, (e) non-cash losses from minority investments, (f) actual cash distributions received from minority investments, (g) to the extent actually reimbursed by insurance, expenses with respect to liability on casualty events or business interruption, and (h) all reasonable transaction expenses related to dispositions and acquisitions of assets, investments and debt and equity offering, and less non-cash income attributable to equity income from minority investments) for a twelve-month period may not be greater than 2.00 to 1.00; and (2) the ratio of EBITDAX to interest expense for a twelve-month period may not be less than 3.00 to 1.00. The Company was in compliance with all covenants at June 30, 2012.

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