Long-Term Debt	6 Months Ended
Long-Term Debt	Jun. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Credit Facility. On February 10, 2017, the $425.0 million reserve-based revolving credit facility (the “First Lien Exit Facility”) was refinanced and replaced by a new $600.0 million credit facility (the “credit facility”). The borrowing base under the credit facility is $425.0 million. This borrowing base was reconfirmed during the April 2018 semi-annual redetermination. The next borrowing base redetermination is scheduled for October 1, 2018. The credit facility matures on March 31, 2020. The outstanding borrowings under the credit facility bear interest based on a pricing grid tied to borrowing base utilization of (a) LIBOR plus an applicable margin that varies from 3.00% to 4.00% per annum, or (b) the base rate plus an applicable margin that varies from 2.00% to 3.00% per annum. Interest on base rate borrowings is payable quarterly in arrears and interest on LIBOR borrowings is payable every one, two, three or six months, at the election of the Company. Quarterly, the Company pays commitment fees assessed at annual rates of 0.50% on any available portion of the credit facility. The Company has the right to prepay loans under the credit facility at any time without a prepayment penalty, other than customary “breakage” costs with respect to LIBOR loans. Upon refinancing of the First Lien Exit Facility, $50.0 million maintained in a restricted cash collateral account, as required by the terms of the First Lien Exit Facility, was released to the Company. The credit facility is secured by (i) first-priority mortgages on at least 95% of the PV-9 valuation of all proved reserves included in the most recently delivered reserve report of the Company, (ii) a first-priority perfected pledge of substantially all of the capital stock owned by each credit party and equity interests in the Royalty Trusts that are owned by a credit party and (iii) a first-priority perfected security interest in substantially all the cash, cash equivalents, deposits, securities and other similar accounts, and other tangible and intangible assets of the credit parties (including but not limited to as-extracted collateral, accounts receivable, inventory, equipment, general intangibles, investment property, intellectual property, real property and the proceeds of the foregoing). The credit facility requires the Company to maintain (i) a maximum consolidated total net leverage ratio, measured as of the end of any fiscal quarter, of no greater than 3.50 to 1.00 and (ii) a minimum consolidated interest coverage ratio, measured as of the end of any fiscal quarter, of no less than 2.25 to 1.00. These financial covenants are subject to customary cure rights. The Company was in compliance with all applicable financial covenants under the credit facility as of June 30, 2018. The credit facility contains customary affirmative and negative covenants, including as to compliance with laws (including environmental laws, ERISA and anti-corruption laws), maintenance of required insurance, delivery of quarterly and annual financial statements, oil and gas engineering reports, maintenance and operation of property (including oil and gas properties), restrictions on the incurrence of liens, indebtedness, asset dispositions, fundamental changes, restricted payments and other customary covenants. The Company was in compliance with these covenants as of June 30, 2018. The credit facility includes events of default relating to customary matters, including, among other things, nonpayment of principal, interest or other amounts; violation of covenants; incorrectness of representations and warranties in any material respect; cross-payment default and cross acceleration with respect to indebtedness in an aggregate principal amount of $25.0 million or more; bankruptcy; judgments involving a liability of $25.0 million or more that are not paid; and ERISA events. Many events of default are subject to customary notice and cure periods. The credit facility also provides that a change in control, as defined therein, constitutes an event of default. In connection with the change in the majority of the members of the Company’s Board that occurred as a result of the 2018 annual meeting in June 2018, the Company entered into a consent and waiver agreement with the administrative agent and certain lenders constituting the majority lenders under the credit facility. The consent and waiver agreement waived any event of default which might have occurred as a result of the change in the majority of the members of the Company’s Board and recognized the new members of the Board as existing members of the Board under the definition of change in control in the credit agreement. The Company had no amounts outstanding under the credit facility at June 30, 2018, and $6.2 million in outstanding letters of credit, which reduce availability under the credit facility on a dollar-for-dollar basis. Building Note. On October 4, 2016 (the “Emergence Date”), in accordance with the joint plan of organization (the "Plan") of the Company and certain of its direct and indirect subsidiaries (collectively, the “Debtors"), the Company entered into the Building Note, which had an initial principal amount of $35.0 million. Net proceeds of $26.8 million received from the sale of the Building Note were remitted to unsecured creditors on the Emergence Date. The Company repaid the Building Note in full in February 2018. Interest was payable on the Building Note at 6% per annum for the first year following the Emergence Date, 8% per annum for the second year following the Emergence Date, and 10% thereafter through maturity. Interest costs were payable in-kind until 90 days after the refinancing of the First Lien Exit Facility, which was May 11, 2017, and approximately $1.3 million in in-kind interest costs were added to the Building Note principal from the Emergence Date. Interest became payable thereafter in cash. The Building Note was set to mature on October 2, 2021 and became prepayable in whole or in part without premium or penalty upon the refinancing of the First Lien Exit Facility. The Building Note was initially recorded at a fair value of $36.6 million upon implementation of fresh start accounting. Prior to repayment, the resulting premium was being amortized to interest expense over the term of the Building Note. Upon repayment, the remaining unamortized premium of $1.2 million was recognized as a gain on extinguishment of debt in the unaudited condensed consolidated statement of operations for the six-month period ended June 30, 2018.