Gastar Exploration (GST) 10-Q 14 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 09, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Registrant Name	Gastar Exploration Inc.
Trading Symbol	GST
Entity Central Index Key	1,431,372
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		218,928,494

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 17,570	$ 13,266
Accounts receivable, net of allowance for doubtful accounts of $1,953	20,906	38,575
Commodity derivative contracts	0	1,370
Prepaid expenses	2,302	960
Total current assets	40,778	54,171
Oil and natural gas properties, full cost method of accounting:
Unproved properties, excluded from amortization	144,386	131,955
Proved properties	1,343,162	1,344,329
Total oil and natural gas properties	1,487,548	1,476,284
Furniture and equipment	3,615	3,838
Total property, plant and equipment	1,491,163	1,480,122
Accumulated depreciation, depletion and amortization	(1,196,792)	(1,155,027)
Total property, plant and equipment, net	294,371	325,095
OTHER ASSETS:
Restricted cash	25	370
Advances to operators	79	82
Other	0	405
Total other assets	104	857
TOTAL ASSETS	335,253	380,123
CURRENT LIABILITIES:
Accounts payable	20,228	24,382
Revenue payable	11,993	11,823
Accrued interest	7,808	7,298
Accrued drilling and operating costs	8,841	9,381
Advances from non-operators	623	1,445
Commodity derivative contracts	13,211	4,416
Commodity derivative premium payable	0	135
Other accrued liabilities	6,457	2,706
Total current liabilities	69,161	61,586
LONG-TERM LIABILITIES:
Long-term debt	373,161	342,952
Commodity derivative contracts	2,634	2,572
Asset retirement obligation	2,577	4,841
Total long-term liabilities	378,372	350,365
Commitments and contingencies (Note 13)	0	0
STOCKHOLDERS’ DEFICIT:
Common stock, par value $0.001 per share; 800,000,000 shares authorized at September 30, 2018 and December 31, 2017, respectively; 218,933,504 and 218,874,418 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	219	219
Additional paid-in capital	821,229	819,554
Accumulated deficit	(933,790)	(851,663)
Total stockholders’ deficit	(112,280)	(31,828)
TOTAL LIABILITIES AND STOCKHOLDERS’ DEFICIT	335,253	380,123
Series A Preferred Stock
STOCKHOLDERS’ DEFICIT:
Preferred stock	41	41
Series B Preferred Stock
STOCKHOLDERS’ DEFICIT:
Preferred stock	$ 21	$ 21

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 1,953	$ 1,953
Preferred stock, shares authorized	40,000,000	40,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	800,000,000	800,000,000
Common stock, shares issued	218,933,504	218,874,418
Common stock, shares outstanding	218,933,504	218,874,418
Series A Preferred Stock
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares issued	4,045,000	4,045,000
Preferred stock, shares outstanding	4,045,000	4,045,000
Liquidation preference per share	$ 25	$ 25
Series B Preferred Stock
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares issued	2,140,000	2,140,000
Preferred stock, shares outstanding	2,140,000	2,140,000
Liquidation preference per share	$ 25	$ 25

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Operations - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	$ 21,514,000	$ 18,228,000	[1]	$ 67,430,000	$ 52,865,000	[1]
(Loss) gain on commodity derivatives contracts	(2,925,000)	(2,896,000)		(17,710,000)	3,782,000
Total revenues and other (loss) gain	18,589,000	15,332,000		49,720,000	56,647,000
EXPENSES:
Production taxes	1,131,000	721,000		2,734,000	1,675,000
Lease operating expenses	5,469,000	6,178,000		17,749,000	16,396,000
Depreciation, depletion and amortization	7,460,000	6,059,000		24,026,000	16,762,000
Impairment of oil and natural gas properties	0	0		17,993,000	0
Accretion of asset retirement obligation	43,000	62,000		139,000	171,000
General and administrative expense	11,567,000	4,067,000		25,396,000	12,482,000
Total expenses	25,670,000	17,523,000		88,037,000	48,673,000
(LOSS) INCOME FROM OPERATIONS	(7,081,000)	(2,191,000)		(38,317,000)	7,974,000
OTHER INCOME (EXPENSE):
Interest expense	(10,468,000)	(10,159,000)		(30,605,000)	(29,744,000)
Loss on early extinguishment of debt	0	0		0	(12,172,000)
Investment income and other	22,000	51,000		62,000	166,000
LOSS BEFORE PROVISION FOR INCOME TAXES	(17,527,000)	(12,299,000)		(68,860,000)	(33,776,000)
Provision for income taxes	0	0		0	0
NET LOSS	(17,527,000)	(12,299,000)		(68,860,000)	(33,776,000)
Dividends on preferred stock	0	(1,206,000)		(7,236,000)	(8,443,000)
Undeclared cumulative dividends on preferred stock	(3,618,000)	(2,412,000)		(3,618,000)	(2,412,000)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (21,145,000)	$ (15,917,000)		$ (79,714,000)	$ (44,631,000)
NET LOSS PER SHARE OF COMMON STOCK ATTRIBUTABLE TO COMMON STOCKHOLDERS:
Basic (in dollars per share)	$ (0.10)	$ (0.08)		$ (0.38)	$ (0.23)
Diluted (in dollars per share)	$ (0.10)	$ (0.08)		$ (0.38)	$ (0.23)
WEIGHTED AVERAGE SHARES OF COMMON STOCK OUTSTANDING:
Basic (shares)	212,192,850	209,072,232		211,296,176	190,745,688
Diluted (shares)	212,192,850	209,072,232		211,296,176	190,745,688
Oil and Condensate
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	$ 17,436,000	$ 12,952,000		$ 54,497,000	$ 37,886,000
Natural Gas
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	1,986,000	2,519,000		5,618,000	7,452,000
NGLs
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	2,092,000	2,757,000	[1]	7,315,000	7,527,000	[1]
Transportation, Treating and Gathering
EXPENSES:
Transportation, treating and gathering	$ 0	$ 436,000		$ 0	$ 1,187,000
[1]	Prior period amounts have not been adjusted under the modified retrospective method.

Condensed Consolidated Statem_2

Condensed Consolidated Statements Of Cash Flows $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss			$ (68,860)	$ (33,776)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	$ 7,460	$ 6,059	24,026	16,762
Impairment of oil and natural gas properties	0	0	17,993	0
Stock-based compensation			3,439	3,990
Total loss (gain) on commodity derivatives contracts	2,925	2,896	17,710	(3,782)
Cash settlements of matured commodity derivatives contracts, net			(6,196)	5,602
Cash premiums paid for commodity derivatives contracts			(552)	0
Amortization of deferred financing costs and debt discount	3,512	3,291	10,030	8,218
Paid-in-kind interest			20,179	0
Accretion of asset retirement obligation	43	62	139	171
Gain on sale of furniture and equipment			7	0
Loss on early extinguishment of debt	0	0	0	12,172
Changes in operating assets and liabilities:
Accounts receivable			16,800	(13,466)
Prepaid expenses			(1,430)	(412)
Accounts payable and accrued liabilities			4,233	13,657
Net cash provided by operating activities			37,518	9,136
CASH FLOWS FROM INVESTING ACTIVITIES:
Development and purchase of oil and natural gas properties			(112,828)	(81,906)
Acquisition of oil and natural gas properties			(269)	(54,462)
Proceeds from sale of oil and natural gas properties			96,349	28,798
Application of proceeds from non-operators			(822)	(1,915)
Advances to operators			(917)	(22)
Purchase of furniture and equipment			(41)	(409)
Net cash used in investing activities			(18,528)	(109,916)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from term loan			0	250,000
Proceeds from convertible notes			0	200,000
Repayment of senior secured notes			0	(325,000)
Repayment of revolving credit facility			0	(84,630)
Loss on early extinguishment of debt			0	(7,011)
Proceeds from issuance of common stock, net of issuance costs			0	56,366
Dividends on preferred stock			(13,267)	(19,298)
Deferred financing charges			0	(10,991)
Tax withholding related to restricted stock award vestings			(1,253)	(586)
Cash settlement of restricted shares			(511)	0
Net cash (used in) provided by financing activities			(15,031)	58,850
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH			3,959	(41,930)
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD			13,636	71,529
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD	17,595	29,599	17,595	29,599
RECONCILIATION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD:
Cash and cash equivalents	17,570	13,266	17,570	13,266
Restricted cash	25	370	25	370
Cash and cash equivalents and restricted cash at end of period	$ 17,595	$ 13,636	$ 17,595	$ 13,636

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	1. Description of Business Gastar Exploration Inc. (the “Company” or “Gastar”) is a pure play Mid-Continent independent energy company engaged in the exploration, development and production of oil, condensate, natural gas and NGLs in the United States. Gastar’s principal business activities include the identification, acquisition, and subsequent exploration and development of oil and natural gas properties with an emphasis on unconventional reserves, such as shale resource plays. Gastar holds a concentrated acreage position in the normally pressured oil window of the STACK Play, an area of central Oklahoma which is home to multiple oil and natural gas-rich reservoirs including the Oswego limestone, Meramec and Osage bench formations within the Mississippi Lime, the Woodford shale and Hunton limestone formations.

Going Concern

Going Concern	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Going Concern	2. Going Concern These unaudited condensed consolidated financial statements as of and for the three and nine months ended September 30, 2018 have been prepared assuming the Company will continue as a going concern, which contemplates realization of assets and the satisfaction of liabilities in the normal course of business for the twelve-month period following the date of issuance of these condensed consolidated financial statements. As previously reported, the Company’s ability to raise additional capital to pursue corporate objectives such as a drilling and development program at a cost of capital that enables the Company to achieve a profit has been significantly adversely affected by its current capital structure. While, historically, the Company has been able to reduce capital expenditures to better match available capital resources, for the reasons described below, the Company has reduced capital expenditures by suspending its operated drilling program. A sustained suspension of the operated drilling program could create the potential for deterioration of its core business. In addition, as a result of the recent further significant deterioration of the Company’s equity trading values, the Company’s common and preferred stock were delisted from the NYSE American LLC stock exchange (the “NYSE American”) and began trading on the OTCQB Venture Market (“OTCQB”). Upon the filing of the Company’s petition for voluntary relief under Chapter 11 of the United States Bankruptcy Code (as described below), the Company’s common and preferred stock were automatically removed from quotation on the OTCQB. The Company’s common and preferred stock commenced trading on the OTC Pink Operated by the OTC Markets Group Inc. (also known as the “OTC Pink”) under the same symbols. To address the foregoing concerns, the Company and its advisors have considered strategic alternatives for recommendation to the board of directors (the “Board”) of the Company. In connection with developing and evaluating alternatives for the Board, the Company and its advisors engaged in a restructuring process to consider potential strategic transactions, including financing, refinancing, sale or merger transactions and encouraged proposals from existing stakeholders and interested third-parties. The Company also elected to suspend its current operated drilling and development program in order to preserve capital for other cash needs including debt service while it considered other strategic alternatives or a possible restructuring of the Company’s debt and equity. On August 21, 2018, the Company publicly filed a process letter that again invited proposals and informed the public how any interested party could participate and make a proposal. The process letter established the bid deadline of October 1, 2018 (the “Bid Deadline”). The Company received three bids on the Bid Deadline, none of which provided a basis for repaying the Company’s indebtedness described below. The Company’s Board determined that none of these proposals presented an actionable alternative. In parallel with the foregoing marketing process, the Company engaged with funds affiliated with Ares regarding a comprehensive financial restructuring transaction. On October 26, 2018, the Company entered into a restructuring support agreement (the “RSA”) with (i) AF V Energy I Holdings, L.P., an affiliate of Ares (the “Consenting Term Lender”) and party to the Third Amended and Restated Credit Agreement, dated March 3, 2017 (as amended, restated, modified, or supplemented form time to time, the “Term Loan”) (ii) certain holders affiliated with Ares (the “Consenting Noteholders”) of the Company’s Convertible Notes due 2022 (the “Notes”) issued pursuant to the indenture dated March 3, 2017 (as amended, restated, modified or supplemented from time to time, the “Indenture”), by and among the Company, as issuer, the guarantors specified therein and Wilmington Trust, National Association, as trustee (the “Trustee”) and collateral agent and (iii) certain holders affiliated with Ares (the “Ares Equity Holders” together with the Consenting Term Lender and the Consenting Noteholders, the “Consenting Parties”) of the Company’s outstanding shares of common stock (the “Existing Common Equity”), to support a restructuring (the “Restructuring”) on the terms set forth in the term sheet annexed to the RSA (the “Restructuring Term Sheet”). The RSA contemplates that the Company and a subsidiary would file for voluntary relief under chapter 11 (the “Chapter 11 Cases”) of the United States Bankruptcy Code (the “Bankruptcy Code”) in a United States Bankruptcy Court (the “Bankruptcy Court”) to implement the Restructuring pursuant to a “prepackaged” plan of reorganization (the “Plan”) and the various related transactions set forth in or contemplated by the Restructuring Term Sheet, the DIP Term Sheet (defined below) and the Exit Facility Term Sheet (defined below). Shortly after entering into the RSA, the Company commenced solicitation of the Plan consistent with section 1126(b) of the Bankruptcy Code, which solicitation concluded on October 30, 2018. On October 31, 2018 (the “Petition Date”), the Company and a subsidiary commenced chapter 11 proceedings and filed the Plan under Chapter 11 of the Bankruptcy Code in the Bankruptcy Court. The Company has filed a motion with the Bankruptcy Court seeking joint administration of their Chapter 11 Cases. The Company will continue to operate its businesses as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. The Company expects ordinary-course operations to continue substantially uninterrupted during and after the Chapter 11 Cases. Pursuant to the terms of the RSA and the Restructuring Term Sheet, the Consenting Parties and other interest holders will receive treatment under the Plan summarized as follows: • holders of claims under the DIP Facility (defined below) arising on account of the New Money Loans (defined below) will receive pro rata participation in the First Lien Exit Facility (defined below) in an amount equal to such claims arising on account of New Money Loans; • holders of claims under the DIP Facility, other than claims arising on account of the New Money Loans, will receive (a) pro rata participation in the Second Lien Exit Facility (defined below) up to an aggregate amount of $200.0 million and (b) to the extent any such claims exceed $200.0 million, such excess will receive a pro rata share of 100% of the common equity in the reorganized Company (the “New Common Equity”); • holders of claims under the Term Loan will receive (a) to the extent there is remaining availability under the Second Lien Exit Facility, pro rata participation in the Second Lien Exit Facility in an equal face amount not to exceed $200.0 million and (b) to the extent any such claims remain outstanding, their pro rata share of 100% of the New Common Equity, subject to dilution upon the issuance of common stock upon exercise of the New Warrants described below and pursuant to a new management incentive plan to be entered into at the discretion of the board of the reorganized Company following emergence from bankruptcy (the “Management Incentive Plan”); • holders of claims under the Indenture will receive their pro rata share of 100% of the New Common Equity, subject to dilution upon the issuance of common stock upon exercise of the New Warrants described below and pursuant to the Management Incentive Plan; • holders of claims arising out of any termination of the Company’s hedging or swap arrangements with Cargill, Inc. and NextEra Energy Marketing, LLC (collectively, the “Hedge Parties”) will receive payment in full in cash in monthly installments through December 2019 pursuant to new secured notes; • holders of claims arising pursuant to statutory liens will receive payment in full in cash in two equal installments on the effective date of the Chapter 11 Cases and six months following such date; • holders of claims arising from general unsecured obligations will receive payment in full in cash as set forth in the Plan; • subject to certain conditions, including that such holders not seek official committee status or the appointment of a trustee or examiner, or object to or otherwise oppose the consummation of the Plan, holders of Gastar’s 8.625% Series A Cumulative Preferred Stock and 10.75% Series B Cumulative Preferred Stock (collectively, the “Existing Preferred Equity”) will receive their pro rata share based on their liquidation preference plus accumulated but unpaid dividends accrued through October 31, 2018 of warrants to purchase 2.5% of the New Common Equity; and • subject to certain conditions, including that such holders not seek official committee status or the appointment of a trustee or examiner, or object to or otherwise oppose the consummation of the Plan, holders of the Existing Common Equity will receive their pro rata share of warrants to purchase 2.5% of the New Common Equity (together with the warrants listed in the previous bullet, the “New Warrants”). In the event that a DIP Toggle Event (as defined in the Restructuring Term Sheet) has occurred, (i) holders of claims arising from general unsecured obligations will receive a pro rata share of the New Common Equity and (ii) all Existing Preferred Equity and Existing Common Equity and Subordinated Securities Claims will be canceled, released, and extinguished without distribution. The occurrence of a DIP Toggle Event will not affect the other treatments contemplated by the RSA as listed above. The RSA contains certain covenants on the part of each of the Company and the Consenting Parties, including limitations on the parties’ ability to pursue alternative transactions, commitments by the Consenting Parties to vote in favor of the Plan and commitments of the Company and the Consenting Parties to negotiate in good faith to finalize the documents and agreements governing the Plan. The RSA also provides for certain conditions to the obligations of the parties and for termination upon the occurrence of certain events, including without limitation, the failure to achieve certain milestones and certain breaches by the parties under the RSA. On October 26, 2018, the Company and the Hedge Parties entered into that certain Hedge Party Restructuring Support Agreement (the “Hedge Party RSA ”). In connection with the Chapter 11 Cases, certain Consenting Parties and/or their affiliates have agreed to provide, on a committed basis, the Company with superpriority debtor-in-possession financing (the “DIP Facility”) on the terms set forth in the term sheet attached to the RSA (the “DIP Term Sheet”). The DIP Term Sheet provides that, among other things: • the DIP Facility shall be comprised of term loans in an aggregate amount of approximately $383.9 million, consisting of $100 million of new money loans (the “New Money Loans”) and approximately $283.9 million of refinanced term loan obligations outstanding under the Term Loan; • upon entry of and subject to a Bankruptcy Court order granting interim approval of the DIP Facility and subject to the satisfaction or waiver of additional conditions precedent, up to $15.0 million of the New Money Loans (the “Interim DIP Tranche”) may be drawn by the Company upon three business days’ notice in one or more draws in an amount that is not less than $2.5 million for the initial draw and not less than $500,000 for each subsequent draw (or, if less, the entire amount of the unused balance of the Interim DIP Tranche); • upon entry of and subject to a Bankruptcy Court order granting final approval (the “Final Order”) of the DIP Facility, and subject to the satisfaction or waiver of additional conditions precedent and an approved budget, up to $100.0 million of New Money Loans, minus any amounts of New Money Loans previously drawn by the Company prior to such date (the resulting amount, the “Final DIP Tranche”) may be drawn by the Company upon three business days’ notice in one or more draws in an amount not less than $500,000 for each draw (or, if less, in the entire amount of the unused balance of the Final DIP Tranche); • upon entry of and subject to the Final Order and subject to the satisfaction or waiver of additional conditions precedent, including the Company having demonstrated to the reasonable satisfaction of the DIP Lenders acting in good faith, the bona fide need for additional liquidity to preserve lease operating rights in response to actions taken or proposed to be taken by third parties, an amount equal to $100.0 million minus the amount of New Money Loans previously drawn by the Company prior to such date (the resulting amount, the “Reserve DIP Tranche”) may be drawn by the Company upon three business days’ notice in one or more draws in an amount not less than $500,000 for each draw (or, if less, in the entire amount of the unused balance of the Reserve DIP Tranche); and • subject to entry of the Final Order, approximately $283.9 million in outstanding term loan obligations consisting of principal and accrued and unpaid interest under the Term Loan as of the date of the commencement of the Chapter 11 Cases will be refinanced by loans (not constituting New Money Loans) funded under the DIP Facility. The Company’s entry into the DIP Facility has been approved by the Bankruptcy Court on an interim basis. The Company’s entry into the DIP Facility on a final basis will be considered by the Bankruptcy Court at a future date. The foregoing description of the DIP Term Sheet does not purport to be complete and is qualified in its entirety by reference to the final, executed documents memorializing the DIP Facility, as approved by the Bankruptcy Court. In connection with the Chapter 11 Cases, certain Consenting Parties and/or their affiliates have agreed to provide, on a committed basis, the Company with an exit financing term loan facility (the “Exit Facility”) on the terms set forth in the term sheet attached to the RSA (the “Exit Facility Term Sheet”). The Exit Facility Term Sheet provides for, among other things, (a) a $100.0 million secured delayed draw term loan facility (the “First Lien Exit Facility”) comprised of (i) term loans consisting of New Money Loans funded under the DIP Facility and deemed funded under the First Lien Exit Facility on the effective date of the Plan and (ii) term loan commitments consisting of an amount equal to any undrawn commitment under the DIP Facility and (b) a secured term loan facility (the “Second Lien Exit Facility”) comprised of up to $200.0 million (as may be reduced by the Exit Lenders in their sole discretion on or prior to the effective date of the Plan), in aggregate principal amount of term loans deemed funded on the effective date of the Plan and consisting of DIP Claims and Term Loan Claims (each as defined in the RSA), as applicable (the loans under the First Lien Exit Facility and the Second Lien Exit Facility, collectively, the “Exit Loans”). The Exit Loans may not be reborrowed once repaid. The Exit Facility is subject to customary closing conditions and approval by the Bankruptcy Court, which has not been obtained at this time. The foregoing description of the Exit Facility Term Sheet does not purport to be complete and is qualified in its entirety by reference to the final, executed documents memorializing the Exit Facility, as approved by the Bankruptcy Court. The Company’s filing of its petition for voluntary relief under Chapter 11 of the Bankruptcy Code constitutes an event of default that accelerated the Company’s obligations under its Term Loan and its Notes. Under the Bankruptcy Code, the creditors under these debt agreements are stayed from taking any action against the Company as a result of an event of default. The transactions described and contemplated by the Plan are all subject to the Bankruptcy Court approval at a future date. There can be no assurances the Bankruptcy Court will ultimately approve the transaction as described above. The Company intends to complete a supplemental marketing process seeking proposal for transactions that are higher and better than the transactions contemplated by the Plan during the Chapter 11 Cases, with a bid deadline of December 17, 2018. The Company intends to publicly disclose further details regarding the supplemental marketing process, including informing interested parties how they may participate and make a proposal, at a future date. In the absence of a higher or better proposal, the Company intends to seek confirmation of the Plan at a hearing currently scheduled for December 20, 2018. Voluntary Reorganization Under Chapter 11 On October 31, 2018, the Company and its subsidiary (collectively, the “Debtors”) commenced Chapter 11 proceedings and filed the Plan for reorganization under Chapter 11 of the Bankruptcy Code with the Bankruptcy Court for the Southern District of Texas. The Debtors have filed a motion with the Bankruptcy Court seeking joint administration of their Chapter 11 Cases under the caption In re: Gastar Exploration Inc., et al. Subject to certain exceptions, under the Bankruptcy Code, the filing of the petitions for voluntary relief in the Chapter 11 Cases automatically enjoined, or stayed, the continuation of most judicial or administrative proceedings or filing of other actions against the Debtors or their property to recover, collect or secure a claim arising prior to the date of the filing of the petitions. Accordingly, although the filing of the voluntary petitions triggered defaults on the Debtors’ debt obligations, creditors are stayed from taking any actions against the Debtors as a result of such defaults, subject to certain limited exceptions permitted by the Bankruptcy Code. Absent an order of the Bankruptcy Court, substantially all of the Debtors’ pre-petition liabilities are subject to settlement under the Bankruptcy Code. For the duration of the Chapter 11 Cases, the Company’s operations and ability to develop and execute its business plan are subject to the risks and uncertainties associated with the Chapter 11 process. As a result of these risks and uncertainties, the number of the Company’s shares of common stock and stockholders, assets, liabilities, officers and/or directors could be significantly different following the outcome of the Chapter 11 Cases, and the description of the Company’s operations, properties and capital plans included in this quarterly report may not accurately reflect its operations, properties and capital plans following the Chapter 11 process. In particular, subject to certain exceptions, under the Bankruptcy Code, the Debtors may assume, assign or reject certain executory contracts and unexpired leases subject to the approval of the Bankruptcy Court and certain other conditions. Generally, the rejection of an executory contract or unexpired lease is treated as a pre-petition breach of such executory contract or unexpired lease and, subject to certain exceptions, relieves the Debtors of performing their future obligations under such executory contract or unexpired lease but entitles the contract counterparty or lessor to a pre-petition general unsecured claim for damages caused by such deemed breach. Counterparties to such rejected contracts or leases may assert unsecured claims in the Bankruptcy Court against the applicable Debtors’ estate for such damages. Generally, the assumption of an executory contract or unexpired lease requires the Debtors to cure existing monetary defaults under such executory contract or unexpired lease and provide adequate assurance of future performance. Accordingly, any description of an executory contract or unexpired lease with the Debtor in this quarterly report, including where applicable a quantification of the Company’s obligations under any such executory contract or unexpired lease with the Debtor is qualified by any overriding rejection rights the Company has under the Bankruptcy Code. Further, nothing herein is or shall be deemed an admission with respect to any claim amounts or calculations arising from the rejection of any executory contract or unexpired lease and the Debtors expressly preserve all of their rights with respect thereto. Although the Company intends to pursue the restructuring in accordance with the terms set forth in the Plan and the RSA, the transactions necessary to implement that restructuring are subject to, among other things, Bankruptcy Court approval, and there can be no assurance that the Company will be successful in completing a restructuring or any other similar transaction on the terms set forth in the Plan and the RSA, on different terms or at all. Furthermore, although the Company will continue to operate its businesses as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court, these factors raise substantial doubt about the Company’s ability to continue as a going concern. These unaudited condensed consolidated financial statements do not include any adjustments that might result from the outcome of the going concern uncertainty. If the Company cannot continue as a going concern, adjustments to the carrying values and classification of its assets and liabilities and the reported amounts of income and expenses could be required and could be material.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies The accounting policies followed by the Company are set forth in the notes to the Company’s audited consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2017 (the “2017 Form 10-K”) filed with the SEC. Please refer to the notes to the consolidated financial statements included in the 2017 Form 10-K for additional details of the Company’s financial condition, results of operations and cash flows. No material item included in those notes has changed except as a result of normal transactions in the interim or as disclosed within this report. The unaudited interim condensed consolidated financial statements of the Company included herein are stated in U.S. dollars and were prepared from the records of the Company by management in accordance with U.S. GAAP applicable to interim financial statements and reflect all normal and recurring adjustments, which are, in the opinion of management, necessary to provide a fair presentation of the results of operations and financial position for the interim periods. Such financial statements conform to the presentation reflected in the 2017 Form 10-K except for revenue which, for the three and nine months ended September 30, 2018, is presented net of treating, transportation and gathering costs pursuant to current authoritative accounting guidance. The current interim period reported herein should be read in conjunction with the financial statements and accompanying notes, including Item 8. “Financial Statements and Supplementary Data, Note 3 – Summary of Significant Accounting Policies,” included in the 2017 Form 10-K. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates with regard to these financial statements include the valuation of convertible debt, estimate of proved oil and natural gas reserve quantities and the related present value of estimated future net cash flows. The unaudited interim condensed consolidated financial statements of the Company include the consolidated accounts of all of its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. Subsequent Events In preparing these financial statements, the Company has evaluated events and transactions for potential recognition or disclosure through the date the financial statements were issued and has disclosed certain subsequent events in these condensed consolidated financial statements, as appropriate. Restricted Cash Cash and cash equivalents that are restricted as to withdrawal or use under the terms of certain contractual agreements are recorded in restricted cash in the current assets section of our consolidated balance sheet. At September 30, 2018 and December 31, 2017, the Company had restricted cash of $25,000 and $370,000, respectively. Accounts Receivable Accounts receivable are reported net of the allowance for doubtful accounts. The allowance for doubtful accounts is determined based on a review of the Company’s receivables. Receivable accounts are charged off when collection efforts have failed or the account is deemed uncollectible. During 2016, the Company determined that a receivable account from a third-party natural gas and NGLs purchaser would no longer be collectible as a result of the third-party purchaser filing for bankruptcy. A summary of the activity related to the allowance for doubtful accounts is as follows: September 30, 2018 December 31, 2017 (in thousands) Allowance for doubtful accounts, beginning of period $ 1,953 $ 1,953 Expense — — Reductions/write-offs — — Allowance for doubtful accounts, end of period $ 1,953 $ 1,953 Recent Accounting Developments Leases. In February 2016, the FASB issued updated guidance to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and enhance disclosures regarding key information about leasing arrangements. Under the new guidance, lessees will be required to recognize a lease liability and a right-of-use asset for all leases. The new lease guidance also simplified the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Additionally, in January 2018, the FASB issued an amendment to the updated guidance to permit an entity to elect an optional transition practical expedient to not evaluate under the new guidance land easements that exist or expire before the adoption of the updated guidance and that were not previously accounted for as leases under previous guidance. In July 2018, the FASB issued an additional amendment that permits an entity to elect an additional transition method to the existing modified retrospective transition requirements. Under the new transition method, an entity could adopt the provisions of this update by recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption without adjustment to the financial statements for periods prior to adoption. Consequently, an entity’s reporting for the comparative periods presented in the financial statements in which it adopts the new leases standard may continue to be in accordance with the previous lease guidance. This amendment also allows a practical expedient that permits lessors to not separate non-lease components from the associated lease component if certain conditions are present. The amendments in this update are effective beginning on January 1, 2019 and should be applied through a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early adoption is permitted. The Company has commenced analyzing its lease contracts but has not yet determined what the effects of adopting this updated guidance will be on its consolidated financial statements. The Company will adopt this updated guidance in the first quarter 2019 and anticipates that it will recognize a right of use asset and lease liability on the adoption date. The Company plans to apply practical expedients provided in the standards update that allow, among other things, not to reassess contracts that commenced prior to the adoption. The Company also anticipates electing a policy not to recognize right of use assets and lease liabilities related to short-term and immaterial leases. Revenue Recognition. On January 1, 2018, the Company adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“ASC 606”) using the modified retrospective method of transition. Under the modified retrospective approach, the standard has been applied to all existing contracts as of the date of initial application with the cumulative effect of applying the standard, if any, recognized in retained earnings. The impact of adoption on our current period results is as follows: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Under ASC 606 Under ASC 605 Increase (Decrease) Under ASC 606 Under ASC 605 Increase (Decrease) (in thousands) (in thousands) Revenues: Oil and condensate $ 17,436 $ 17,448 $ (12 ) $ 54,497 $ 54,530 $ (33 ) Natural gas 1,986 2,752 (766 ) 5,618 7,708 (2,090 ) NGLs 2,092 2,593 (501 ) 7,315 8,629 (1,314 ) Total oil and condensate, natural gas and NGLs revenues $ 21,514 $ 22,793 $ (1,279 ) $ 67,430 $ 70,867 $ (3,437 ) Expenses: Transportation, treating and gathering $ — $ 1,279 $ (1,279 ) $ — $ 3,437 $ (3,437 ) Net income (loss) $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ — Retained earnings $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ — The primary impact to our revenues as a result of the adoption of ASC 606 is the recording of transportation, treating, gathering and compression expenses (“Post-Production Expenses”) as a direct reduction to revenues instead of our historical practice of presenting such expenses gross in transportation, treating and gathering. These changes are due to the conclusion that the Company represents the agent in the sale of natural gas and NGLs under its gas processing and marketing agreements with midstream entities in accordance with the control model in ASC 606. As a result, the Company is required to record revenue on a net basis for amounts expected to be received from third-party customers through the marketing process, with Post-Production Expenses incurred subsequent to control of the product(s) transferring to the midstream entity at the wellhead being netted against revenue.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2018
Property Plant And Equipment [Abstract]
Property, Plant and Equipment	4. Property, Plant and Equipment The amount capitalized as oil and natural gas properties was incurred for the purchase and development of various properties in the U.S., specifically in the State of Oklahoma. The following table summarizes the components of unproved properties excluded from amortization at the dates indicated: September 30, 2018 December 31, 2017 (in thousands) Unproved properties, excluded from amortization: Drilling in progress costs $ 800 $ 4,772 Acreage acquisition costs 122,455 113,191 Capitalized interest 21,131 13,992 Total unproved properties excluded from amortization $ 144,386 $ 131,955 The full cost method of accounting for oil and natural gas properties requires a quarterly calculation of a limitation on capitalized costs, often referred to as a full cost ceiling calculation. The ceiling is the present value (discounted at 10% per annum) of estimated future cash flow from proved oil, condensate, natural gas and NGLs reserves reduced by future operating expenses, development expenditures, abandonment costs (net of salvage) to the extent not included in oil and natural gas properties pursuant to authoritative guidance and estimated future income taxes thereon. To the extent that the Company's capitalized costs (net of accumulated depletion and deferred taxes) exceed the ceiling at the end of each reporting period, the excess must be written off to expense for such period. Once incurred, this impairment of oil and natural gas properties is not reversible at a later date even if oil and natural gas prices increase. The ceiling calculation is determined using a mandatory trailing 12-month unweighted arithmetic average of the first-day-of-the-month commodities pricing and costs in effect at the end of the period, each of which are held constant indefinitely (absent specific contracts with respect to future prices and costs) with respect to valuing future net cash flows from proved reserves for this purpose. The 12-month unweighted arithmetic average of the first-day-of-the-month commodities prices are adjusted for basis and quality differentials in determining the present value of the proved reserves. The table below sets forth relevant pricing assumptions utilized in the quarterly ceiling test computations for the respective periods noted before adjustment for basis and quality differentials: 2018 Total Year to Date Impairment September 30 June 30 March 31 Henry Hub natural gas price (per MMBtu) (1) $ 2.91 $ 2.92 $ 3.00 WTI oil price (per Bbl) (1) $ 63.43 $ 57.67 $ 53.49 Impairment recorded (pre-tax) (in thousands) $ 17,993 $ — $ 17,993 $ — 2017 Total Year to Date Impairment September 30 June 30 March 31 Henry Hub natural gas price (per MMBtu) (1) $ 3.00 $ 3.01 $ 2.73 WTI oil price (per Bbl) (1) $ 49.81 $ 48.95 $ 47.61 Impairment recorded (pre-tax) (in thousands) $ — $ — $ — $ — (1) For the respective periods, oil and natural gas prices are calculated using the trailing 12-month unweighted arithmetic average of the first-day-of-the-month prices based on Henry Hub spot natural gas prices and WTI spot oil prices. The Company could potentially incur additional ceiling test impairments in the future should commodities prices decline or the value of its estimates of proved reserves declines. However, it is difficult to project future impairment charges in light of numerous variables involved. The Company’s proved reserves estimates and their estimated discounted value and standardized measure will also be impacted by changes in lease operating costs, future development costs, production, exploration and development activities and estimated future income taxes. The ceiling limitation calculation is not intended to be indicative of the fair market value of the Company’s proved reserves or future results. The Company’s undeveloped reserves previously classified as proved, other than the PUD reserves associated with certain wells developed prior to June 30, 2018 or in the process of drilling and completion at June 30, 2018, were reclassified as unproved at June 30, 2018 due to the inability to meet the reasonable certainty criteria for proved reserves, as prescribed under the SEC rules, primarily due to the uncertainties regarding the availability and timing of funds required to develop these reserves. As of September 30, 2018, the Company has no PUD reserves since all prior PUD reserves recognized at June 30, 2018 have been converted to proved developed. WEHLU Sale On January 23, 2018, the Company entered into a definitive agreement of sale and purchase (the “Sale Agreement”) to divest its interest in the West Edmund Hunton Lime Unit (“WEHLU”) and adjacent undeveloped acreage to Revolution Resources, LLC, for $107.5 million, subject to, among other customary adjustments, adjustments for a property sale effective date of October 1, 2017 (the “WEHLU Sale”). Pursuant to the Sale Agreement, the WEHLU Sale closed on February 28, 2018. After effective date and other adjustments of approximately $9.9 million primarily related to revenues and direct operating expenses, net cash proceeds from the WEHLU Sale were approximately $97.6 million. The WEHLU Sale was reflected as a reduction to the full cost pool and no gain or loss was recorded related to the divestiture as such divestiture did not result in a significant change to the depletion rate. The following unaudited pro forma results for the three months ended September 30, 2017 and the nine months ended September 30, 2018 and 2017 show the effect on the Company's consolidated results of operations as if the WEHLU Sale had occurred at the beginning of the periods presented. The pro forma results are the result of excluding from the statement of operations of the Company the revenues and direct operating expenses for the properties divested adjusted for (1) the reduction in asset retirement obligation liabilities and accretion expense for the properties divested and (2) the reduction in depreciation, depletion and amortization expense as a result of the divestiture. As a result, certain estimates and judgments were made in preparing the pro forma adjustments. For the Three Months Ended September 30, 2017 (in thousands, except (Unaudited) Revenues $ 6,749 Net loss $ (19,133 ) Loss per share: Basic $ (0.09 ) Diluted $ (0.09 ) For the Nine Months Ended September 30 2018 2017 (in thousands, except (Unaudited) Revenues $ 42,983 $ 28,796 Net loss $ (81,973 ) $ (55,356 ) Loss per share: Basic $ (0.39 ) $ (0.26 ) Diluted $ (0.39 ) $ (0.26 ) STACK Leasehold Acquisition On March 22, 2017, the Company completed the acquisition of additional working and net revenue interests in approximately 66 gross (9.5 net) producing wells and 5,670 net acres of additional undeveloped STACK Play leasehold in Kingfisher County, Oklahoma, effective March 1, 2017, for $51.4 million (the “STACK Leasehold Acquisition”). Prior to the completion of the STACK Leasehold Acquisition, the Company held an interest in the majority of acquired producing wells and acreage. The Company accounted for the STACK Leasehold Acquisition as an asset acquisition. Development Agreement On October 14, 2016, the Company executed an agreement with STACK Exploration LLC (the “Investor”) (the “Development Agreement”) to jointly develop up to 60 Gastar operated wells in the STACK Play in Kingfisher County, Oklahoma (the “Drilling Program”). The Drilling Program targeted the Meramec and Osage formations within the Mississippi Lime in a contract area within three townships covering approximately 32,900 gross (21,200 net) undeveloped mineral acres under leases held by the Company. The Company serves as the operator of all Drilling Program wells. Under the Development Agreement, the Investor funded 90% of the Company’s working interest portion of drilling and completion costs to initially earn 80% of the Company’s working interest in each new well (in each case, proportionately reduced by other participating working interests in the well). As a result, the Company paid 10% of its working interest portion of such costs for 20% of its original working interest. The proposed Drilling Program wells were to be mutually developed in three tranches of 20 wells each. The locations of the first 20 wells, comprised of 18 Meramec formation wells and two Osage formation wells, were mutually agreed upon by the Company and the Investor. Participation in the second tranche of 20 Drilling Program wells was to be at the election of the Investor and the third tranche of 20 wells would require mutual consent. On July 31, 2017, the Investor elected not to participate in the second tranche of wells. With respect to each 20-well tranche, when the Investor has achieved an aggregate 15% internal rate of return for its investment in the tranche, Investor’s interest will be reduced from 80% to 40% of the Company’s original working interest and the Company’s working interest increases from 20% to 60% of the original working interest. When a tranche internal rate of return of 20% is achieved by the Investor, Investor’s working interest decreases to 10% and the Company’s working interest increases to 90% of the working interest originally owned by the Company. If and when the final reversion of working interest in the completed 20 well tranche should occur, the Investor has the right, but not the obligation, for a period of six months to cause the Company to purchase the Investor’s remaining interest in the 20 wells in the Drilling Program (the “WI Tail”) for such tranche (the “Investor Put Right”) for fair market value by applying the methodology to determine a 15% discounted present value as defined by the Development Agreement. If the Investor fails to exercise the Investor Put Right within the six-month period after achieving final reversion, then for a period of six months thereafter, the Company shall have the right, but not the obligation, to purchase the WI Tail from the Investor on the same fair market value approach of the Investor Put Right. If final reversion has not been achieved by August 19, 2024, Investor will, for a period of six months thereafter, have the right to cause the Company to buy Investor’s then-current interest in the Drilling Program wells at an agreed upon valuation. Based on current commodity prices, well cost and production performance of the completed wells drilled in the first tranche, the 15% of internal rate of return is not anticipated to be achieved. By December 31, 2017, the Company and the Investor had completed all 20 gross (15.8 net; 3.2 net to the Company) wells within the first tranche of the Drilling Program.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	5. Long-Term Debt The table below provides a reconciliation of the Company’s long-term debt balance as presented in the condensed consolidated balance sheets for the periods presented: September 30, 2018 December 31, 2017 (in thousands) Term Loan, principal balance (1) $ 276,778 $ 256,599 Less: Unamortized deferred financing costs (4,002 ) (4,724 ) Unamortized debt discount (19,873 ) (22,464 ) Term Loan, net $ 252,903 $ 229,411 Notes, principal balance $ 162,500 $ 162,500 Less: Unamortized deferred financing costs (2,217 ) (2,631 ) Unamortized debt discount (40,025 ) (46,328 ) Notes, net $ 120,258 $ 113,541 Total long-term debt $ 373,161 $ 342,952 (1) Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end. Ares Investment Transactions On March 3, 2017, certain funds (the “Purchasers”) managed indirectly by Ares purchased from the Company for cash (i) $125.0 million aggregate principal amount of its Notes sold at par, which Notes, subject to the receipt of approval of the Company’s stockholders which was obtained on May 2, 2017, are convertible into common stock or, in certain circumstances, cash in lieu of common stock or a combination of cash and shares of common stock as described below and (ii) 29,408,305 shares of common stock for a purchase price of $50.0 million at a purchase price of $1.7002 per share based on a 30-trading day volume weighted average price (“VWAP”) determined on February 15, 2017. In addition, an affiliate of Ares concurrently loaned the Company $250.0 million pursuant to the Term Loan, as borrower, the guarantors party thereto, AF V Energy I Holdings, L.P., a fund managed indirectly by Ares Management LLC, as lender, and Wilmington Trust, National Association, as Administrative Agent as further described below. The proceeds from the sale of the Notes, the common stock and the Term Loan were used to fully repay and redeem the Company’s prior Revolving Credit Facility (as defined below) and to satisfy and discharge its $325.0 million of 8.625% senior secured notes due May 2018, which were satisfied and discharged on March 3, 2017 by irrevocably calling for redemption and depositing with the indenture trustee cash in the amount of the redemption price of 102.156% of their principal amount plus accrued and unpaid interest to the redemption date of March 24, 2017, and to pay the expenses from the Ares transactions. In order to provide funding for the STACK Leasehold Acquisition and a portion of the Company’s 2017 capital budget, on March 21, 2017, the Purchasers purchased from the Company for cash an additional $75.0 million aggregate principal amount of its Notes sold at par (the “Additional Notes”). The Notes, including the Additional Notes, were issued with conversion rights that were subject to the approval of holders of issued and outstanding common stock (other than the Purchasers), which approval was obtained May 2, 2017 (the “Requisite Stockholder Approval”). Pursuant to the purchase agreement for the Additional Notes, upon receipt of Requisite Stockholder Approval, Purchasers and the Company exchanged $37.5 million principal amount of the Additional Notes for (a) 25,456,521 newly issued shares of common stock (the “Repurchase Shares”) and (b) 2,000 shares of the Company’s Special Voting Preferred Stock, par value $0.01 per share (the “Mandatory Repurchase”). The terms of Mandatory Repurchase, which was effected May 5, 2017, provided for one Repurchase Share issued for each $1.4731 of outstanding principal of the repurchased Notes, which was based on the 10-day VWAP of the common stock for the period ended March 17, 2017. The exchange reduced the aggregate principal amount of issued and outstanding Notes from $200.0 million to $162.5 million at June 30, 2017, which principal amount remained outstanding at September 30, 2018. Term Loan On March 3, 2017, the Company entered into a credit agreement for the Term Loan. The Term Loan bears interest at a per annum rate equal to 8.5%, payable on a quarterly basis on each March 31, June 30, September 30 and December 31 of each year, commencing March 31, 2017. The Term Loan has a scheduled maturity of March 3, 2022. In addition, prepayment of the Term Loan is subject to an interest “make-whole” and prepayment premium, such that any prepayment of the loans thereunder prior to the stated maturity date shall be subject to the payment of a prepayment premium, and depending on the date of such prepayment, the applicable interest “make-whole” amount, with the amount of such prepayment premium decreasing over the life of the Term Loan. The Term Loan is guaranteed by the Company’s sole domestic subsidiary and will be guaranteed by all of the Company's future domestic subsidiaries formed during the term of the Term Loan. The Term Loan is secured by a first-priority lien on substantially all of the assets of the Company and its subsidiaries, excluding certain assets as customary exceptions. The Term Loan contains various customary covenants for credit facilities of this type, including, among others, restrictions on granting liens, incurrence of other indebtedness, payments of certain dividends and other restricted payments, engaging in transactions with affiliates, dispositions of assets and other, in each case subject to certain baskets and exceptions. All outstanding amounts owed become due and payable upon the occurrence of certain usual and customary events of default, including among others (i) failure to make payments; (ii) non-performance of covenants and obligations continuing beyond any applicable grace period; and (iii) the occurrence of a change in control of the Company, as defined in the Term Loan. As of September 30, 2018, no events of default had occurred. The Company’s voluntary filing of its petition in the Chapter 11 Cases on October 31, 2018 constituted an event of default that accelerated the Company’s obligations under the Term Loan. Under the Bankruptcy Code, the creditors under the Term Loan and other debt agreements are stayed from taking any action against the Company as a result of an event of default. See Note 2 – Going Concern for additional information about the Chapter 11 Cases and the proposed Plan The Company accounted for the Term Loan in accordance with guidance relating to “ Debt with Conversion and Other Options On March 20, 2017, the Company, together with the parties thereto, entered into Amendment No. 1 to the Term Loan credit agreement which amendment permitted the issuance of the Additional Notes. On August 2, 2017, the Company, together with the parties thereto, entered into an Amendment No. 2 to Term Loan credit agreement (“Amendment No. 2”). Amendment No. 2 amended the Term Loan, to among other things, (i) allow for the payment of pay in kind (“PIK”) interest on the Term Loan at the applicable PIK percentage and (ii) increased the applicable interest rate for periods ending after June 30, 2017 from 8.5% per annum to 10.25% per annum. Amendment No. 2 allows the Company to elect to PIK upon proper notice 100% of interest payments due after June 30, 2017 and prior to December 31, 2018 and at the Company’s election, PIK between 0% and 50% of any interest payments occurring after December 31, 2018 (other than interest due on the maturity date or the date of any repayment or prepayment). The Term Loan interest rate increased from 8.5% per annum to 10.25% per annum for all interest periods post June 30, 2017 and the PIK interest shall be payable by capitalizing and adding such amounts to the outstanding principal amount of the Term Loan on the applicable interest payment date. On September 18, 2017, the Company, together with the parties thereto, entered into Amendment No. 3 to the Term Loan credit agreement (“Amendment No. 3”). Amendment No. 3 amended the Term Loan to, among other things, expressly provide that certain assignments of oil and natural gas properties made or to be made by the Company to Red Bluff Resources Operating, LLC (“Red Bluff”), pursuant to the Red Bluff Purchase and Sale Agreement dated October 19, 2016 between the Company and Red Bluff (“Red Bluff PSA”), are permitted by the Term Loan and are not subject to the mandatory prepayment provisions applicable to “Asset Sales” under the Term Loan. On June 29, 2018, the Company, together with the parties thereto, entered into Amendment No. 4 to the Term Loan credit agreement (“Amendment No. 4”). Amendment No. 4, among other things, (i) reduced the period the Company could cure a default resulting from the failure to comply with certain covenants applicable to the Term Loan from 30 days to 15 days, (ii) waived certain defaults under the Term Loan and (iii) prohibited the Company from making cash dividends or distributions on or with respect to its capital stock, other than cash dividends on its Series A Preferred Stock and Series B Preferred Stock declared for the month of June 2018. The carrying amounts of the Term Loan for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Term Loan, principal balance (1) $ 276,778 $ 256,599 Less: Unamortized deferred financing costs (4,002 ) (4,724 ) Unamortized debt discount (19,873 ) (22,464 ) Term loan, net $ 252,903 $ 229,411 (1) Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end. Indenture and Notes The principal terms of the Notes are governed by the Indenture. Pursuant to the Indenture, the Notes were issued for cash at par, bear interest at 6.0% per annum and will mature on March 1, 2022, unless earlier repurchased, redeemed or converted in accordance with the terms of the Indenture. Interest is payable on the Notes on each March 1, June 1, September 1 and December 1 of each year, commencing on June 1, 2017. Pursuant to the Indenture, Requisite Stockholder Approval was required on or before July 3, 2017 to approve the conversion rights of the Notes (including the Additional Notes) to be convertible at the option of the holder into shares of common stock based on the terms of the Indenture. Requisite Stockholder Approval was obtained on May 2, 2017 at a special meeting of stockholders. The interest rate on the Notes was subject to an increase in certain circumstances if the Company fails to comply with certain obligations under a Registration Rights Agreement and on the Notes in the case of certain issuances of common stock by the Company at a price below $1.7002 per share (subject to adjustment). The Notes are secured by a second-priority lien on substantially all of the assets of the Company and its sole subsidiary. If at least a majority of the Notes issued pursuant to the Securities Purchase Agreement dated February 16, 2017 (the “Purchase Agreement”) cease to be held by affiliates of Ares as provided in the Indenture, the liens securing the Notes will be released and substantially all of the restrictive covenants in the Indenture will terminate. The Indenture restricts the ability of the Company and certain of its subsidiaries to, among other things: (i) pay dividends or make other distributions in respect of the Company’s capital stock or make other restricted payments; (ii) incur additional indebtedness and issue preferred stock; (iii) make certain dispositions and transfers of assets; (iv) engage in transactions with affiliates; (v) create liens; (vi) engage in certain business activities that are not related to oil and gas; and (vii) impair any security interest. These covenants are subject to a number of exceptions and qualifications. The Indenture provides that a number of events will constitute an Event of Default (as defined in the Indenture), including, among other things: (i) a failure to pay the Notes when due at maturity, upon redemption or repurchase; (ii) failure to pay interest for 30 days; (iii) the Company’s failure to deliver certain notices; (iv) a default in the Company’s obligation to convert the Notes; (v) the Company’s failure to comply with certain covenants relating to merger, consolidation or sale of assets; (vi) the Company’s failure to comply, for 60 days following notice, with any of the other covenants or agreements in the Indenture; (vii) a default, which is not cured within 30 days, by the Company or any Restricted Subsidiaries (as defined in the Indenture) with respect to any mortgages or any indebtedness for money borrowed of at least $15 million; (viii) one or more final judgments against the Company or any of its Restricted Subsidiaries for the payment of at least $15 million; (ix) the Company’s failure to make any payments required under that certain development agreement, which is not cured within 30 days; (x) causing any Guarantee (as defined in the Indenture) to cease to be in full force and effect; (xi) the cessation to be in full force and effect of any of the collateral agreements entered into with respect to the Notes; and (xii) certain events of bankruptcy or insolvency. In the case of an Event of Default arising from certain events of bankruptcy or insolvency with respect to the Company, all outstanding Notes will become due and payable immediately without further action or notice. If any other Event of Default occurs and is continuing, the Trustee or the holders of at least 25% in aggregate principal amount of the then outstanding Notes may declare all the Notes to be due and payable immediately. At September 30, 2018, no Event of Default had occurred. The Company’s voluntary filing of its petition in the Chapter 11 Cases on October 31, 2018 constituted an event of default that accelerated the Company’s obligations under the Notes. Under the Bankruptcy Code, the creditors under the Notes and other debt agreements are stayed from taking any action against the Company as a result of an event of default. See Note 2 – Going Concern On June 29, 2018, the Company, the subsidiary guarantor named therein and the Trustee, entered into a Second Supplemental Indenture (the “Second Supplemental Indenture”), which supplements the Indenture. The Second Supplemental Indenture, among other things, (i) waived certain defaults, (ii) reduced the period the Company could cure certain covenant defaults under the Indenture from 60 days to 15 days and (iii) prohibited the Company and its subsidiary from making cash dividends or distributions on or with respect to its capital stock, other than cash dividends on its Series A Preferred Stock and its Series B Preferred Stock declared for the month of June 2018. In accordance with accounting guidance relating to “ Debt with Conversion and Other Options” The carrying amount of the liability component of the Notes for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Notes, principal balance $ 162,500 $ 162,500 Less: Unamortized deferred financing costs (2,217 ) (2,631 ) Unamortized debt discount (40,025 ) (46,328 ) Notes, net $ 120,258 $ 113,541 The carrying amount of the equity components of the Notes recorded in additional paid in capital for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Value of conversion option $ 77,626 $ 77,626 Debt issuance costs attributable to conversion option $ (2,164 ) $ (2,164 ) Total $ 75,462 $ 75,462 Second Amended and Restated Revolving Credit Facility On June 7, 2013, the Company entered into the Second Amended and Restated Credit Agreement among the Company, Wells Fargo Bank, National Association, as Administrative Agent, Collateral Agent, Swing Line Lender and Issuing Lender and the lenders named therein (the “Revolving Credit Facility”). The Revolving Credit Facility had a scheduled maturity of November 14, 2017. On January 10, 2017, the Company, together with the parties thereto, entered into an amendment to the Second Amended and Restated Credit Agreement (“Amendment No. 10”), which amended the Revolving Credit Facility to, among other things, permit the payment of certain cash dividends on its preferred stock, including the dividends declared payable on January 31, 2017, provided that (i) the Company’s borrowing base was correspondingly reduced in the amount of any such dividend payment and (ii) the Company paid down its outstanding indebtedness under the Revolving Credit Facility in the amount of any resulting borrowing base deficiency. Under Amendment No. 10, payment of the declared January 2017 dividend and monthly preferred stock cash dividends through May 2017 was permitted contingent upon the satisfaction of certain conditions, including but not limited to, (i) the absence of any defaults or borrowing base deficiency, (ii) for any dividends declared and paid in respect of April 2017 and May 2017, having cash liquidity (including any available borrowings under the Revolving Credit Facility) of more than $30.0 million and (iii) paying any permitted dividends solely from proceeds received by the Company from sales of equity since November 30, 2016 (including through the Company’s at-the-market issuance sales agreement with a third-party sales agent to sell, from time to time, shares of the Company’s common stock (the “ATM Program”). Under Amendment No. 10, the Company also agreed to pay down indebtedness under its Revolving Credit Facility by at least an additional $8.1 million by April 30, 2017. On March 3, 2017, the Company used a portion of the net proceeds from the transactions described in this Note 5 under the caption “Ares Investment Transactions” above to fully repay all of the $69.2 million borrowings outstanding under the Revolving Credit Facility (which was terminated on such date). Senior Secured Notes At December 31, 2016, the Company had $325.0 million aggregate principal amount of 8 5/8% Senior Secured Notes due May 15, 2018 (the “Former Notes”) outstanding under an indenture by and among the Company, the Guarantors named therein (the “Guarantors”), Wells Fargo Bank, National Association, as Trustee (in such capacity, the “Former Notes Trustee”) and Collateral Agent. The Former Notes bore interest at a rate of 8.625% per year, payable semi-annually in arrears on May 15 and November 15 of each year. On March 3, 2017, the redemption price plus interest on all of the Company’s outstanding $325.0 million principal of the Former Notes was funded to satisfy and discharge the Former Notes from a portion of the net proceeds from the transactions described in this Note 5 under the caption “Ares Investment Transactions” above. All of the Former Notes were satisfied and discharged on March 3, 2017 by irrevocably calling for redemption and depositing with the indenture trustee cash in the amount of the redemption price of 102.156% of the principal amount, or principal plus an additional $7.0 million, plus accrued and unpaid interest to the redemption date of March 24, 2017. Additionally, the Company wrote-off $5.2 million of remaining unamortized deferred financing costs related to the Former Notes upon redemption.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements The Company’s financial assets and liabilities are measured at fair value on a recurring basis. The Company discloses its recognized non-financial assets and liabilities, such as asset retirement obligations, unproved properties and other property and equipment, at fair value on a non-recurring basis. For non-financial assets and liabilities, the Company is required to disclose information that enables users of its financial statements to assess the inputs used to develop these measurements. The Company assesses its unproved properties for impairment whenever events or circumstances indicate the carrying value of those properties may not be recoverable. The fair value of the unproved properties is measured using an income approach based upon internal estimates of future production levels, current and future prices, drilling and operating costs, discount rates, current drilling plans and favorable and unfavorable drilling activity on the properties being evaluated and/or adjacent properties, which are Level 3 (as defined below) inputs. Should an impairment of unproved properties occur, the value of the impaired properties would be reclassified into proved properties in the full cost pool subject to depletion. As no other fair value measurements are required to be recognized on a non-recurring basis at September 30, 2018, no additional disclosures are provided. As defined in the guidance, fair value is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). To estimate fair value, the Company utilizes market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable. The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (“Level 1”) and the lowest priority to unobservable inputs (“Level 3”). The three levels of the fair value hierarchy are as follows: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. The Company’s cash equivalents consist of short-term, highly liquid investments, which have maturities of 90 days or less, including sweep investments and money market funds. • Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. • Level 3 inputs are measured based on prices or valuation models that require inputs that are both significant to the fair value measurement and less observable from objective sources. These inputs may be used with internally developed methodologies or third party broker quotes that result in management’s best estimate of fair value. The Company’s valuation models consider various inputs including (a) quoted forward prices for commodities, (b) time value, (c) volatility factors and (d) current market and contractual prices for the underlying instruments. Significant increases or decreases in any of these inputs in isolation would result in a significantly higher or lower fair value measurement. Level 3 instruments are commodity costless collars, index swaps, basis and fixed price swaps and put and call options to hedge oil, natural gas and NGLs price risk. At each balance sheet date, the Company performs an analysis of all applicable instruments and includes in Level 3 all of those whose fair value is based on significant unobservable inputs. The fair values derived from counterparties and third-party brokers are verified by the Company using publicly available values for relevant NYMEX futures contracts and exchange traded contracts for each derivative settlement location. Although such counterparty and third-party broker quotes are used to assess the fair value of its commodity derivative instruments, the Company does not have access to the specific assumptions used in its counterparties valuation models. Consequently, additional disclosures regarding significant Level 3 unobservable inputs were not provided and the Company does not currently have sufficient corroborating market evidence to support classifying these contracts as Level 2 instruments. As required, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values below incorporates various factors, including the impact of the counterparty’s non-performance risk with respect to the Company’s financial assets and the Company’s non-performance risk with respect to the Company’s financial liabilities. The Company has not elected to offset the fair value amounts recognized for multiple derivative instruments executed with the same counterparty, but reports them gross on its consolidated balance sheets. Transfers between levels are recognized at the end of the reporting period. There were no transfers between levels during the 2018 and 2017 periods. The following tables set forth by level within the fair value hierarchy the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2018 and December 31, 2017: Fair value as of September 30, 2018 Level 1 Level 2 Level 3 Total (in thousands) Assets: Commodity derivative contracts $ — $ — $ — $ — Liabilities: Commodity derivative contracts — — (15,845 ) (15,845 ) Total $ — $ — $ (15,845 ) $ (15,845 ) Fair value as of December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Assets: Commodity derivative contracts $ — $ — $ 1,370 $ 1,370 Liabilities: Commodity derivative contracts — — (6,988 ) (6,988 ) Total $ — $ — $ (5,618 ) $ (5,618 ) The table below presents a reconciliation of the assets and liabilities classified as Level 3 in the fair value hierarchy for the three and nine months ended September 30, 2018 and 2017. Level 3 instruments presented in the table consist of net derivatives that, in management’s opinion, reflect the assumptions a marketplace participant would have used at September 30, 2018 and 2017. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) Balance at beginning of period $ (15,730 ) $ 9,436 $ (5,618 ) $ 7,512 Total (losses) gains included in earnings (2,925 ) (2,896 ) (17,710 ) 3,782 Purchases — — 552 470 Issuances — — — — Settlements (1) 2,810 (2,179 ) 6,931 (7,403 ) Balance at end of period $ (15,845 ) $ 4,361 $ (15,845 ) $ 4,361 The amount of total gains (losses) for the period included in earnings attributable to the change in mark to market of commodity derivatives contracts still held at September 30, 2018 and 2017 $ 433 $ (4,672 ) $ (9,026 ) $ (1,898 ) (1) Included in gain (loss) on commodity derivatives contracts on the condensed consolidated statements of operations. At September 30, 2018, the estimated fair value of accounts receivable and accounts and revenue payables approximates their carrying value due to their short-term nature. The estimated fair value of the Notes excluding the conversion feature at September 30, 2018 was $113.1 million calculated based on the fair value of similar non-convertible debt instruments (Level 2) since an observable quoted price of the Notes or a similar asset or liability is not readily available. The estimated fair value of the Term Loan at September 30, 2018 was $241.0 million calculated based on the fair value of similar debt instruments (Level 2) since an observable price of the Term Loan or a similar asset or liability is not readily available.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	7. Revenue from Contracts with Customers Disaggregation of Revenue The following represents a disaggregation of revenues and a reconciliation of total revenues as reported in the condensed consolidated statement of operations to revenue from contracts with customers: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 (1) 2018 2017 (1) (in thousands) Revenues Oil and condensate $ 17,436 $ 12,952 $ 54,497 $ 37,886 Natural gas 1,986 2,519 5,618 7,452 NGLs 2,092 2,757 7,315 7,527 Total revenues from contracts with customers $ 21,514 $ 18,228 $ 67,430 $ 52,865 (1) Prior period amounts have not been adjusted under the modified retrospective method. Revenue Recognition Oil, condensate, natural gas and NGLs revenues are recognized at the point in time that control of the product is transferred to the customer and collectability is reasonably assured. A more detailed summary of the underlying contracts that give rise to revenue and method of recognition are included below. Oil and Condensate Sales Under the Company’s oil and condensate sales contracts, the Company delivers all or a specified percentage of the crude oil production from specified leases to the nominated delivery point which is the outlet flange of the Company’s lease facility or at unit storage tanks. The Company sells oil and condensate production at the delivery point and collects an agreed-upon index price, net of applicable transport differential. The Company recognizes revenue when control transfers to the purchaser at the delivery point at the net price received. Natural Gas and NGLs Sales Under the Company’s gas processing contracts, the Company delivers all or a specified percentage of natural gas production to a midstream processing entity at the wellhead or the inlet of the midstream processing entity’s system. The midstream processing entity processes the natural gas, sells the resulting NGLs and residue gas to third parties and pays the Company for the NGLs and residue gas with deductions for Post-Production Expenses. The NGLs are subject to an incremental NGLs pricing formula based upon a percentage of NGLs extracted from the Company’s wet gas. For the Company’s gas processing contracts, the Company evaluates whether it is the principal or the agent. For the Company’s existing contracts, it has concluded that it is the agent and the midstream processing entity is the Company’s customer, and therefore, the Company recognizes revenue when control transfers to the midstream processing entity for the net amount of the proceeds received. If for future contracts the Company was to conclude that it is the principal with the ultimate third party being the customer, the Company would recognize revenue for those contracts on a gross basis, with Post-Production Expenses presented gross as expenses. Imbalances The Company recognizes revenue for all oil, condensate, natural gas and NGLs sold to purchasers regardless of whether the sales are proportionate to the Company’s ownership interest in the property. Production imbalances are recognized as a liability to the extent an imbalance on a specific property exceeds the Company’s share of remaining proved oil and natural gas reserves. The Company had no material imbalances at September 30, 2018 or 2017. Significant Judgments Principal versus Agent The Company engages in various types of transactions in which midstream entities process its wet gas and, in some scenarios, subsequently market resulting NGLs and residue gas to third-party customers on the Company’s behalf, such as gas processing contracts. These types of transactions require judgment to determine whether the Company is the principal or the agent in the contract and, as a result, whether revenues are recorded gross or net. For the Company’s existing contracts, the Company has determined that it represents the agent in the sale of products under certain gas processing and marketing agreements with midstream entities in accordance with the control model in ASC 606. As a result, the Company presents revenue on a net basis for amounts expected to be received from third-party customers through the marketing process, with Post-Production Expenses incurred subsequent to control of the product(s) transferring to the midstream entity being netted against revenue. Transaction Price Allocated to Remaining Performance Obligations A significant number of the Company’s product sales are short-term in nature with a contract term of one year or less. For those contracts, the Company has utilized the practical expedient in ASC 606-10-50-14 that exempts it from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. For the Company’s product sales that have a contract term greater than one year, the Company has utilized the practical expedient in ASC 606-10-50-14A that states that it is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under these sales contracts, each unit of product generally represents a separate performance obligation; therefore future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Contract Balances Under the Company’s customer contracts, the Company receives a remittance advice confirming purchased volumes and pricing from its customers once the Company’s performance obligations have been satisfied, at which point payment is unconditional. Accordingly, the Company’s contracts do not give rise to contract assets or liabilities under ASC 606. All of the Company’s revenue accounts receivable balances are attributable to revenues from contracts with customers. Prior-period Performance Obligations The Company records revenue in the month its production is delivered to the purchaser. However, settlement statements and payment may not be received for 30 to 90 days after the date production is delivered, and as a result, the Company is required to estimate the amount of production that was delivered to the purchaser and the price that will be received for the sale of the product including any transportation and other deductions. The Company uses its knowledge of its properties, historical performance, contractual data, the anticipated effect of weather conditions during the month of production and prevailing market as the basis for these estimates. The Company records the variances between its estimates and the actual amounts received in the month payment is received and such variances have historically not been material. For the three and nine months ended September 30, 2018, revenue recognized in the reporting period related to performance obligations satisfied in prior reporting periods was not material.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activity	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activity	8. Derivative Instruments and Hedging Activity The Company maintains a commodity price risk management strategy that uses derivative instruments to minimize significant, unanticipated earnings fluctuations that may arise from volatility in commodity prices. The Company uses costless collars, index, basis and fixed price swaps and put and call options to hedge oil, condensate, natural gas and NGLs price risk. All derivative contracts are carried at their fair value on the balance sheet and all changes in value are recorded in the condensed consolidated statements of operations in (loss) gain on commodity derivatives contracts. For the three months ended September 30, 2018 and 2017, the Company reported a gain of $433,000 and a loss of $4.7 million, respectively, in the condensed consolidated statements of operations related to the change in the fair value of its commodity derivative contracts still held at September 30, 2018 and 2017. For the nine months ended September 30, 2018 and 2017, the Company reported losses of $9.0 million and $1.9 million, respectively, in the condensed consolidated statements of operations related to the change in the fair value of its commodity derivative contracts still held at September 30, 2018 and 2017. For the three months ended September 30, 2018 and 2017, the Company reported a loss of $3.4 million and a gain of $1.8 million, respectively, in the condensed consolidated statements of operations for the settlement of derivatives during the respective periods. For the nine months ended September 30, 2018 and 2017, the Company reported a loss of $8.7 million and a gain of $5.7 million, respectively, in the condensed consolidated statements of operations for the settlement of derivatives during the respective periods. As of September 30, 2018, the following crude derivative transactions were outstanding with the associated notional volumes and weighted average underlying hedge prices: Settlement Period Derivative Instrument Average Daily Volume (1) Total of Notional Volume Base Fixed Price Floor (Long) Short Put Ceiling (Short) (in Bbls) October to December 2018 Costless three-way collar 1,700 156,400 $ — $ 47.50 $ 37.50 $ 57.85 October to December 2018 Fixed price swap 500 46,000 $ 61.60 $ — $ — $ — October to December 2018 Fixed price swap 600 55,200 $ 51.20 $ — $ — $ — January to September 2019 Costless three-way collar 2,000 546,000 $ — $ 47.50 $ 37.50 $ 59.70 October to December 2019 Costless three-way collar 1,900 174,800 $ — $ 47.50 $ 37.50 $ 59.70 January to September 2019 Fixed price swap 700 191,100 $ 50.40 $ — $ — $ — October to November 2019 Fixed price swap 600 36,600 $ 50.40 $ — $ — $ — December 2019 Fixed price swap 416 12,896 $ 50.40 $ — $ — $ — (1) Crude volumes hedged include oil, condensate and certain components of our NGLs production. As of September 30, 2018, the following natural gas derivative transactions were outstanding with the associated notional volumes and weighted average underlying hedge prices: Settlement Period Derivative Instrument Average Daily Volume Total of Notional Volume Base Fixed Price Floor (Long) Short Put Ceiling (Short) (in MMBtus) October to December 2018 Fixed price swap 1,550 142,600 $ 3.01 $ — $ — $ — As of September 30, 2018, all of the Company’s economic derivative hedge positions were with large institutions, which are not known to the Company to be in default on their derivative positions. The Company is exposed to credit risk to the extent of non-performance by the counterparties in the derivative contracts discussed above; however, the Company does not anticipate non-performance by such counterparties. None of the Company’s derivative instruments contain credit-risk related contingent features. On October 26, 2018, the Company and the Hedge Parties entered into the Hedge Party RSA to effectively terminate the Company’s current hedge positions and replace such with new secured notes to be paid in monthly installments through December 2019 (the “Hedge Party Secured Notes”) . The Hedge Party Secured Notes will be secured by an uncapped first priority security interest in the collateral that secures the Exit Facility which security interest and lien shall rank pari passu with the liens granted to the Company’s senior-most creditors (with respect to debt for borrowed money). On November 1, 2018, the Company’s current hedge positions were terminated and the value of the Hedge Party Secured Notes was determined to be $12.4 million, subject to approval by the Bankruptcy Court. The Hedge Party Secured Notes mature on December 31, 2019 during which time no interest shall accrue unless a default occurs under the terms thereof. Funds in the Exit Facility will be available to make payments under the Hedge Party Secured Notes. Additional Disclosures about Derivative Instruments and Hedging Activities The tables below provide information on the location and amounts of derivative fair values in the condensed consolidated statement of financial position and derivative gains and losses in the condensed consolidated statement of operations for derivative instruments that are not designated as hedging instruments: Fair Values of Derivative Instruments Derivative Assets (Liabilities) Fair Value Balance Sheet Location September 30, 2018 December 31, 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts Current assets $ — $ 1,370 Commodity derivative contracts Current liabilities (13,211 ) (4,416 ) Commodity derivative contracts Long-term liabilities (2,634 ) (2,572 ) Total derivatives not designated as hedging instruments $ (15,845 ) $ (5,618 ) Amount of Gain (Loss) Recognized in Income on Derivatives For the Three Months Ended September 30, Location of (Loss) Gain Recognized in Income on Derivatives 2018 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts Loss on commodity derivatives contracts $ (2,925 ) $ (2,896 ) Total $ (2,925 ) $ (2,896 ) Amount of Gain (Loss) Recognized in Income on Derivatives For the Nine Months Ended September 30, Location of (Loss) Gain Recognized in Income on Derivatives 2018 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts (Loss) gain on commodity derivatives contracts $ (17,710 ) $ 3,782 Total $ (17,710 ) $ 3,782

Capital Stock

Capital Stock	9 Months Ended
	Sep. 30, 2018
Stockholders Equity Note [Abstract]
Capital Stock	9. Capital Stock Common Stock On May 7, 2015, the Company entered into the ATM Program. The shares were issued pursuant to the Company’s then-existing effective shelf registration statement on Form S-3, as amended (Registration No. 333-193832). The Company registered shares having an aggregate offering price of up to $50.0 million. For the period January 1, 2017 to February 20, 2017, the Company sold 5,447,919 shares through the ATM Program for net proceeds of $8.3 million. The ATM Program expired on February 24, 2017. On March 3, 2017, the Purchasers purchased for cash (i) $125.0 million aggregate principal amount of Notes sold at par and (ii) 29,408,305 shares of common stock for a purchase price of $50.0 million before offering costs and expenses. The common stock sale was priced based on a 30-trading day VWAP of $1.7002 determined on February 15, 2017 the date immediately prior to the signing date of the Purchase Agreement with Purchasers in respect to such sale. On March 21, 2017, the Company sold to the Purchasers an additional $75.0 million aggregate principal amount of Notes. Pursuant to the purchase agreement for the Additional Notes, after obtaining the Requisite Stockholder Approval, on May 5, 2017, the Company and the Purchasers exchanged $37.5 million aggregate principal amount of the outstanding Additional Notes for the issuance of 25,456,521 shares of common stock to Purchasers of the Mandatory Repurchase. The Notes are convertible into shares of common stock as described in more detail in Note 5. On June 27, 2017, the Company’s stockholders approved an amendment to the Company’s certificate of incorporation to increase the number of authorized shares of common stock from 550,000,000 to 800,000,000, which amendment became effective on July 24, 2017. At September 30, 2018, there were 218,933,504 shares of the Company’s common stock issued and outstanding. Preferred Stock Pursuant to the Company’s certificate of incorporation, the Company has 40,000,000 shares of preferred stock authorized with a par value of $0.01 per share. The Company has designated 10,000,000 of such shares to constitute its 8.625% Series A Cumulative Preferred Stock (the “Series A Preferred Stock”) and 10,000,000 of such shares to constitute its 10.75% Series B Cumulative Preferred Stock (the “Series B Preferred Stock”). The Series A Preferred Stock and the Series B Preferred Stock each have a liquidation preference of $25.00 per share. On March 22, 2017, the Company designated 2,000 of such shares as Special Voting Preferred Stock with a liquidation preference of $0.01 for each share, which is junior and subordinate to the right of the holders of any shares of any other existing or future series of preferred stock. Series A Preferred Stock At September 30, 2018, there were 4,045,000 shares of the Series A Preferred Stock issued and outstanding with a $25.00 per share liquidation preference. The Series A Preferred Stock ranks senior to the Company's common stock and on parity with the Series B Preferred Stock with respect to the payment of dividends and distribution of assets upon liquidation, dissolution or winding up. The Series A Preferred Stock is subordinated to all of the Company’s existing and future debt and all future capital stock designated as senior to the Series A Preferred Stock. The Series A Preferred Stock cannot be converted into common stock, but may be redeemed, at the Company’s option for $25.00 per share plus any accrued and unpaid dividends. There is no mandatory redemption of the Series A Preferred Stock. The Company paid monthly dividends on the Series A Preferred Stock at a fixed rate of 8.625% per annum of the $25.00 per share liquidation preference through March 2016. Effective March 9, 2016, the Revolving Credit Facility prohibited the payment of cash dividends on the Company’s preferred stock commencing April 2016. Pursuant to Amendment No. 10 to the Company’s Revolving Credit Facility, on January 10, 2017, the Company declared a special cash dividend on the Series A Preferred Stock to pay in full all accumulated and unpaid cash dividends accrued since April 1, 2016 at an annualized 8.625% through the payment date. The Series A Preferred Stock January 2017 dividend of $7.3 million was paid on January 31, 2017 to holders of record at the close of business on January 20, 2017, which paid all unpaid dividends that accumulated in respect to the Series A Preferred Stock at such time. Thereafter, all monthly cash dividends on the Series A Preferred Stock were paid for each month through July 2017. On August 1, 2017, primarily in response to the decline in oil prices and to preserve liquidity, the Company elected to suspend Series A Preferred Stock dividends commencing August 2017, which suspension remained in effect through March 2018. On April 9, 2018, the Company declared a special cash dividend on the Series A Preferred Stock to pay in full all accumulated and unpaid cash dividends accrued since August 1, 2017 at an annualized 8.625% through the payment date. The Series A Preferred Stock April 2018 dividend of $6.5 million was paid on April 30, 2018 to holders of record at the close of business on April 20, 2018, which paid all unpaid dividends that accumulated in respect to the Series A Preferred Stock at such time. The Company continued to declare and pay dividends on the Series A Preferred Stock through June 30, 2018. On June 11, 2018, the Company elected to suspend the declaration and payment of monthly cash dividends on the Series A Preferred Stock commencing July 2018. On June 29, 2018, the Company entered into Amendment No. 4 to the Term Loan and into the Second Supplemental Indenture, both of which prohibit the Company from making cash dividends or distributions on or with respect to its capital stock, other than cash dividends on its Series A Preferred Stock and its Series B Preferred Stock declared for the month of June 2018, which were paid on July 2, 2018. Dividends on the Series A Preferred Stock accumulate regardless of whether any such dividends are declared. If the Company has accumulated, accrued and unpaid cash dividends in any calendar month within four calendar quarters, then commencing in the calendar month following the first month in such fourth calendar quarter in which cash dividends are not paid in full, and until accumulated dividends are paid in full for four calendar quarters with the last two calendar quarters’ dividends paid in cash, (i) the fixed dividend rate of Series A Preferred Stock each increases by 2.00% per annum, (ii) the Company will be required to issue a dividend of common stock to pay accrued and unpaid dividends based on then current market value determined in accordance with the certificate of designations applicable to the Series A Preferred Stock, if such dividends are not paid in cash, provided it has sufficient capital surplus to pay such a dividend and can otherwise pay a dividend under state law, and (iii) the holders of Series A Preferred Stock and Series B Preferred Stock, voting as a single class, will have the right to elect up to two additional directors to the board of directors of the Company. If the Company’s common stock ceases to be listed on a national securities exchange or a national securities market, “pay in kind” dividends of additional shares of Series A Preferred Stock may be payable in lieu of cash or common stock dividends. For the three months ended September 30, 2018, the Company recognized undeclared cumulative dividends on preferred stock of $2.2 million for the Series A Preferred Stock. For the three months ended September 30, 2017, the Company recognized and paid cash dividends of $727,000 and recognized undeclared cumulative dividends of $1.5 million for the Series A Preferred Stock. For the nine months ended September 30, 2018, the Company recognized dividends of $4.4 million, recognized undeclared cumulative dividends of $2.2 million and paid cash dividends of $8.0 million, including $3.6 million of 2017 undeclared dividends, for the Series A Preferred Stock. For the nine months ended September 30, 2017, the Company recognized dividends of $5.1 million, recognized undeclared cumulative dividends of $1.5 million and paid cash dividends of $11.6 million, including $6.5 million of 2016 undeclared dividends, for the Series A Preferred Stock. As of September 30, 2018, there were $2.2 million of accumulated and unpaid dividends on the outstanding Series A Preferred Stock. Series B Preferred Stock At September 30, 2018, there were 2,140,000 shares of the Series B Preferred Stock issued and outstanding with a $25.00 per share liquidation preference. The Series B Preferred Stock ranks senior (to the extent of its stated liquidation preference and any accumulated and unpaid dividends) to the Company’s common stock and on parity with Series A Preferred Stock with respect to the payment of dividends and distribution of assets upon liquidation, dissolution or winding up. The Series B Preferred Stock are subordinated to all of the Company’s existing and future debt and all future capital stock designated as senior to the Series B Preferred Stock. Except upon a change in ownership or control, the Series B Preferred Stock may not be redeemed before November 15, 2018, at or after which time it may be redeemed at the Company’s option for $25.00 per share in cash. Following a change in ownership or control, the Company will have the option to redeem the Series B Preferred Stock within 90 days of the occurrence of the change in control, in whole but not in part for $25.00 per share in cash, plus accrued and unpaid dividends (whether or not declared), up to, but not including the redemption date. If the Company does not exercise its option to redeem the Series B Preferred Stock upon a change of ownership or control, the holders of the Series B Preferred Stock have the option to convert the shares of Series B Preferred Stock into the Company's common stock based upon on an average common stock trading price then in effect but limited to an aggregate of 11.5207 shares of the Company’s common stock per share of Series B Preferred Stock, subject to certain adjustments. If the Company exercises any of its redemption rights relating to shares of Series B Preferred Stock, the holders of Series B Preferred Stock will not have the conversion right described above with respect to the shares of Series B Preferred Stock called for redemption. There is no mandatory redemption of the Series B Preferred Stock. The Company paid monthly dividends on the Series B Preferred Stock at a fixed rate of 10.75% per annum of the $25.00 per share liquidation preference through March 2016. Effective March 9, 2016, the Revolving Credit Facility prohibited the payment of cash dividends on the Company’s preferred stock commencing April 2016. Pursuant to Amendment No. 10 to the Company’s Revolving Credit Facility, on January 10, 2017, the Company declared a special cash dividend on the Series B Preferred Stock to pay in full all accumulated and unpaid cash dividends since April 1, 2016 at an annualized 10.75% through the payment date. The Series B Preferred Stock January 2017 dividend in the amount of $4.8 million was paid on January 31, 2017 to holders of record at the close of business on January 20, 2017, which paid all unpaid dividends that accumulated in respect to the Series B Preferred Stock at such time. Thereafter, all monthly cash dividends on the Series B Preferred Stock were paid for each month through July 2017. On August 1, 2017, primarily in response to the decline in oil prices and to preserve liquidity, the Company elected to suspend Series B Preferred Stock dividends commencing August 2017, which suspension remained in effect through March 2018. On April 9, 2018, the Company declared a special cash dividend on the Series B Preferred Stock to pay in full all accumulated and unpaid cash dividends accrued since August 1, 2017 at an annualized 10.75% through the payment date. The Series B Preferred Stock April 2018 dividend of $4.3 million was paid on April 30, 2018 to holders of record at the close of business on April 20, 2018, which paid all unpaid dividends that accumulated in respect to the Series B Preferred Stock at such time. The Company continued to declare and pay dividends on the Series B Preferred Stock through June 30, 2018. On June 11, 2018, the Company elected to suspend the declaration and payment of monthly cash dividends on the Series B Preferred Stock commencing July 2018. On June 29, 2018, the Company entered into Amendment No. 4 to the Term Loan and into the Second Supplemental Indenture, both of which prohibit the Company from making cash dividends or distributions on or with respect to its capital stock, other than cash dividends on its Series A Preferred Stock and its Series B Preferred Stock declared for the month of June 2018, which were paid on July 2, 2018. Dividends on the Series B Preferred Stock will accumulate regardless of whether any such dividends are declared. If the Company has accumulated, accrued and unpaid cash dividends in any calendar month within four calendar quarters, then commencing in the calendar month following the first month in such fourth calendar quarter in which cash dividends are not paid in full, and until accumulated dividends are paid in full for four calendar quarters with the last two calendar quarters’ dividends paid in cash, (i) the fixed dividend rate of Series B Preferred Stock each increases by 2.00% per annum, (ii) the Company will be required to issue a dividend of common stock to pay accrued and unpaid dividends based on then current market value determined in accordance with the certificate of designations applicable to the Series B Preferred Stock, if such dividends are not paid in cash, provided it has sufficient capital surplus to pay such a dividend and can otherwise pay a dividend under state law, and (iii) the holders of Series A Preferred Stock and Series B Preferred Stock, voting as a single class, will have the right to elect up to two additional directors to the board of directors of the Company. If the Company’s common stock ceases to be listed on a national securities exchange or a national securities market, “pay in kind” dividends of additional shares of Series B Preferred Stock may be payable in lieu of cash or common stock dividends. For the three months ended September 30, 2018, the Company recognized undeclared cumulative dividends on preferred stock of $1.4 million for the Series B Preferred Stock. For the three months ended September 30, 2017, the Company recognized and paid cash dividends of $479,000 and recognized undeclared cumulative dividends of $959,000 for the Series B Preferred Stock. For the nine months ended September 30, 2018, the Company recognized dividends of $2.9 million, recognized undeclared cumulative dividends of $1.4 million and paid cash dividends of $5.3 million, including $2.4 million of 2017 undeclared dividends, for the Series B Preferred Stock. For the nine months ended September 30, 2017, the Company recognized dividends of $3.4 million, undeclared cumulative dividends of $959,000 and paid cash dividends of $7.7 million, including $4.4 million of 2016 undeclared dividends, for the Series B Preferred Stock. As of September 30, 2018, there were $1.4 million of accumulated and unpaid dividends on the outstanding Series B Preferred Stock. Other Share Issuances The following table provides information regarding the issuances and forfeitures of common stock pursuant to the Company's long-term incentive plan for the periods indicated: For the Three Months Ended September 30, 2018 For the Nine Months Ended September 30, 2018 Other share issuances: Shares of restricted common stock granted — 3,231,531 Shares of restricted common stock vested 324,746 5,708,107 Shares of restricted common stock surrendered upon vesting/repurchase (1) 105,018 2,588,258 Shares of restricted common stock forfeited 137,089 584,187 _________________ (1) Represents shares of common stock forfeited in connection with the payment of estimated withholding taxes on shares of restricted common stock that vested during the period and vested shares of restricted stock repurchased from certain executives. On June 27, 2017, the Company’s stockholders approved an amendment to the Gastar Exploration Inc. Long-Term Incentive Plan (the “LTIP”), effective May 2, 2017, to, among other things, increase the number of shares of common stock reserved for issuance under the LTIP by 14,000,000 shares of common stock. There were 7,953,365 shares of common stock available for issuance under the LTIP at September 30, 2018. Shares Reserved At September 30, 2018, the Company had 127,400 stock options outstanding and a target number of 888,888 performance based units outstanding.

Interest Expense

Interest Expense	9 Months Ended
	Sep. 30, 2018
Interest Expense [Abstract]
Interest Expense	10. Interest Expense The following table summarizes the components of interest expense for the periods indicated: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) Interest expense: Cash and accrued $ 2,468 $ 2,438 $ 7,357 $ 19,644 Paid in kind 7,147 6,459 20,689 6,459 Amortization of deferred financing costs and debt discount 3,512 3,291 10,030 8,218 Capitalized interest (2,659 ) (2,029 ) (7,471 ) (4,577 ) Total interest expense $ 10,468 $ 10,159 $ 30,605 $ 29,744

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes For the three and nine months ended September 30, 2018 and 2017, respectively, the Company did not recognize a current income tax benefit or provision as the Company has a full valuation allowance against assets created by net operating losses generated. The Company believes it more likely than not that the assets will not be utilized. The Company had no deferred income tax expense (benefit) for the three and nine months ended September 30, 2018 and 2017. In connection with the Company’s recent equity and convertible debt transactions during 2017, the Company determined that the utilization of net operating losses in future years is subject to limitations by reason of an “ownership change” as defined under Section 382 of the Internal Revenue Code (“Section 382 Limitation”). Any utilization of the Company’s net operating loss carryforwards and other tax credit carryforwards will be subject to the Section 382 Limitation. The Company is subject to examination of income tax filings in the U.S. and various state jurisdictions for the periods 2010 and forward and the foreign jurisdiction of Canada for the tax periods 2000 through 2013 due to the Company’s continued loss position in such jurisdictions. The Company is currently under audit by the U.S. Internal Revenue Service for the taxable period ended December 31, 2014.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings per Share	12. Earnings per Share In accordance with the provisions of current authoritative guidance, basic earnings or loss per share is computed on the basis of the weighted average number of common shares outstanding during the periods. Diluted earnings or loss per share is computed based upon the weighted average number of common shares outstanding plus the assumed issuance of common shares for all potentially dilutive securities. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands, except per share and share data) Net loss attributable to common stockholders $ (21,145 ) $ (15,917 ) $ (79,714 ) $ (44,631 ) Weighted average common shares outstanding - basic 212,192,850 209,072,232 211,296,176 190,745,688 Weighted average common shares outstanding - diluted 212,192,850 209,072,232 211,296,176 190,745,688 Net loss per share of common stock attributable to common stockholders: Basic $ (0.10 ) $ (0.08 ) $ (0.38 ) $ (0.23 ) Diluted $ (0.10 ) $ (0.08 ) $ (0.38 ) $ (0.23 ) Common shares excluded from denominator as anti-dilutive: Unvested restricted shares 91,152 553,671 711,520 750,499 Unvested PBUs 888,888 1,654,841 204,742 713,911 Convertible notes 73,520,769 73,520,769 73,520,769 63,319,752 Total 74,500,809 75,729,281 74,437,031 64,784,162

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Litigation Gastar Exploration Inc. v. Christopher McArthur (Cause No.: 2015-77605) 157th Judicial District Court, Harris County, Texas. On December 29, 2015, Gastar filed suit against Christopher McArthur (“McArthur”) in the District Court of Harris County, Texas. The lawsuit arises from a demand letter sent by McArthur to Gastar in which he claimed to be party to an agreement with Gastar that entitled him to be paid $2.75 million for services rendered. In August 2016, McArthur filed an amended answer admitting he had no agreement with the Company. As a result, Gastar believes McArthur’s claim has been effectively resolved. Gastar has also pursued a claim in this action against McArthur for tortious interference with an existing contract. On October 17, 2018, the Court entered a judgment in favor of Gastar on this tortious interference claim. Gastar is currently pursuing collection efforts. Torchlight Energy Resources, Inc., Torchlight Energy, Inc. v. Husky Ventures, Inc., et al., (Cause No. 429-01961-2016) 429th Judicial District Court in Collin County, Texas. Torchlight Energy Resources, Inc. and Torchlight Energy, Inc. (collectively “Torchlight”) brought a lawsuit against the Company, two of its executive officers, its chairman of the board of directors and a former director of the Company on May 3, 2016 in Collin County, Texas (the “Torchlight Lawsuit”). The Torchlight Lawsuit arose primarily out of Torchlight’s business dealings with Husky Ventures, Inc. (“Husky”) in Oklahoma. Husky and several of its employees and affiliates were also defendants in the Torchlight Lawsuit. As part of settlement negotiations between Husky and the Company in a separate lawsuit, Husky informed the Company that it had agreed to repurchase assets from Torchlight that Husky had previously sold to Torchlight (the “Torchlight Assets”). Husky offered to sell those Torchlight Assets to the Company. In the Purchase and Sale Agreement between Torchlight and Husky (the “Purchase and Sale Agreement”), Torchlight expressly acknowledged that the Torchlight Assets were to be sold to the Company and released the Company from any claims arising out of the sale of the Torchlight Assets. Despite this release, Torchlight alleged multiple causes of action against the Company and its officers and directors arising out of the sale of the Torchlight Assets and Torchlight’s other business dealings it had with Husky. On August 17, 2016, plaintiffs nonsuited, without prejudice, their claims against the former chairman of the board. On May 22, 2017, the court granted the Company’s motion for summary judgment and dismissed all of the plaintiffs’ claims against the Company and the Company’s other officers and directors in their entirety. The Company filed a counterclaim against Torchlight for breach of the release in the Purchase and Sale Agreement. On April 26, 2018, the Court granted, in part, the Company’s motion for summary judgment on its breach-of-contract counterclaim and left for trial only the question of the Company’s damages. On May 23, 2018, Torchlight and the Company settled the breach-of-contract counterclaim, and on May 24, 2018, the Court dismissed with prejudice all claims and counterclaims between Torchlight and the Company in the Torchlight Lawsuit. PennMarc Resources II, LP, et al v. Gastar Exploration USA, Inc., et al, (Civil Action No. 18-C-220 H.) Circuit Court of Marshall County, West Virginia; Venable Royalty, Ltd. et al v. Gastar Exploration USA, Inc., et al, (Civil Action No 18-C-227.) Circuit Court of Marshall County, West Virginia. These lawsuits are related to a prior lawsuit filed by the same plaintiffs in 2017: The plaintiffs are royalty owners under various leases taken by or assigned to the Company. The leases cover property in Marshall County, West Virginia. The leases are among other assets that were assigned to THQ Appalachia, LLC pursuant to a purchase and sale agreement dated February 12, 2016. In the original lawsuit, the plaintiffs alleged that the Company breached the leases by making deductions for post-production costs that were not authorized by the terms of the leases. The plaintiffs also alleged that the unauthorized deductions were not shown on their monthly royalty statements and the failure to detail the deduction of these costs was fraudulent. The plaintiffs asserted claims for breach of contract, breach of fiduciary duty and fraudulent concealment. The plaintiffs sought compensatory damages and punitive damages. The Company successfully moved to dismiss the plaintiffs’ claims in December 2017, arguing that some claims were subject to arbitration while others were premature because the plaintiffs had failed to provide written notice of a breach, as required by the leases. The Court granted the Company’s motion to dismiss in July 2018 and dismissed the plaintiffs’ claims without prejudice. After the motion was granted, a number of the plaintiffs complied with the leases’ pre-suit notification requirement by sending the Company formal notices of breach. In its response to the notices, the Company asserted that it had paid royalties correctly during its ownership of the leases. In October of 2018, PennMarc Resources II, LP refiled its lawsuit along with several of the other original plaintiffs. Shortly thereafter, two more of the original plaintiffs, Venable Royalty, Ltd. and Venro, Ltd., filed a separate but identical lawsuit. In both lawsuits, the plaintiffs allege the Company breached the leases by improperly deducting post-production costs. The plaintiffs assert a claim for breach of contract and seek compensatory damages, equitable accounting, and declaratory relief. The Company is still reviewing the lawsuits and has not yet filed an answer. Eagle Natrium LLC v. Gastar Exploration USA, Inc., Cause No. GD-14-7208, In the Court of Common Pleas of Allegheny County, Pennsylvania. On April 22, 2014, Eagle Natrium LLC (“Eagle”), a wholly-owned subsidiary of Axiall Corporation, filed a complaint against the Company in the Court of Common Pleas of Allegheny County, Pennsylvania seeking to enjoin Gastar’s hydraulic fracturing and completion operations on three wells drilled from Gastar’s Goudy pad in Marshall County, West Virginia, or conducting any activity that poses a substantial risk of harm to Eagle’s brine operations. Gastar was the operator of approximately 16,000 acres in Marshall County, West Virginia, including a 3,300 gross acre oil and gas lease adjacent to Eagle’s facilities. Eagle asserted its right to relief based on certain of the lessor’s rights which were assigned to Eagle by the lessor solely as they relate to the brine and related facilities. A hearing on the request for preliminary injunction was held in the summer of 2014. After considering the evidence presented at the hearing and the party’s briefing, the court issued an order on October 21, 2014 denying the request for a preliminary injunction. In January 2015, Gastar began completion operations and has since completed the three wells drilled from its Goudy pad that formed the basis of Eagle’s complaint. In 2016, the Company amended its answer and has added counterclaims seeking damages from Eagle as a result of the proceedings. Specifically, Gastar has asserted a breach of contract claim, seeking damages for lost revenues, rig up and rig down costs and attorney’s fees relating to the Pennsylvania lawsuit filed by Eagle. Eagle has also maintained its breach of contract claim against the Company. The Court has bifurcated the proceeding into a separate liability and damages phase. On June 25, 2018, the Court commenced a six-day bench trial on liability. A decision on the parties’ respective liability remains pending. The Company has been expensing legal costs on these proceedings as they are incurred. The Company is party to various legal proceedings arising in the normal course of business. The ultimate outcome of each of these matters cannot be absolutely determined, and the liability the Company may ultimately incur with respect to any one of these matters in the event of a negative outcome may be in excess of amounts currently accrued for with respect to such matters. Net of available insurance and performance of contractual defense and indemnity obligations, where applicable, management does not believe any such matters will have a material adverse effect on the Company’s financial position, results of operations or cash flows. The commencement of the Chapter 11 Cases automatically stayed certain actions against the Company, including actions to collect pre-petition indebtedness or to exercise control over the property of the Company’s bankruptcy estates, and the Company intends to seek authority to pay all general claims in the ordinary course of business notwithstanding the commencement of the Chapter 11 Cases in a manner consistent with the RSA. The Plan filed in the Chapter 11 Cases, if confirmed as contemplated by the RSA, will provide for the treatment of claims against the Company’s bankruptcy estates, including pre-petition liabilities that have not otherwise been satisfied or addressed during the Chapter 11 Cases. Retention Payments On August 31, 2018, each of Stephen P. Roberts, Michael A. Gerlich and Jerry R. Schuyler entered into retention bonus letters (each a “Retention Bonus Letter”) On October 25, 2018, Gastar entered into amendments (the “Retention Bonus Amendments”) to the

Statement of Cash Flows - Suppl

Statement of Cash Flows - Supplemental Information	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Statement of Cash Flows - Supplemental Information	14. Statement of Cash Flows – Supplemental Information The following is a summary of the supplemental cash paid and non-cash transactions for the periods indicated: For the Nine Months Ended September 30, 2018 2017 (in thousands) Cash paid for interest, net of capitalized amounts $ (114 ) $ 17,770 Non-cash transactions: Capital expenditures included in accounts payable and accrued drilling costs $ (4,496 ) $ 12,176 Capital expenditures included in accounts receivable $ — $ 76 Capital expenditures excluded from prepaid expenses $ (88 ) $ — Asset retirement obligation included in oil and natural gas properties $ 178 $ 403 Asset retirement obligation sold $ (2,581 ) $ (1,533 ) Application of advances to operators $ 920 $ 24 Non-cash financing charges excluded from accounts payable and accrued liabilities $ — $ 19 Undeclared cumulative dividends on preferred stock $ 3,618 $ 2,412 Conversion of convertible debt to equity $ — $ 37,500

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Accounting	The unaudited interim condensed consolidated financial statements of the Company included herein are stated in U.S. dollars and were prepared from the records of the Company by management in accordance with U.S. GAAP applicable to interim financial statements and reflect all normal and recurring adjustments, which are, in the opinion of management, necessary to provide a fair presentation of the results of operations and financial position for the interim periods. Such financial statements conform to the presentation reflected in the 2017 Form 10-K except for revenue which, for the three and nine months ended September 30, 2018, is presented net of treating, transportation and gathering costs pursuant to current authoritative accounting guidance. The current interim period reported herein should be read in conjunction with the financial statements and accompanying notes, including Item 8. “Financial Statements and Supplementary Data, Note 3 – Summary of Significant Accounting Policies,” included in the 2017 Form 10-K.
Subsequent Events	Subsequent Events In preparing these financial statements, the Company has evaluated events and transactions for potential recognition or disclosure through the date the financial statements were issued and has disclosed certain subsequent events in these condensed consolidated financial statements, as appropriate.
Restricted Cash	Restricted Cash Cash and cash equivalents that are restricted as to withdrawal or use under the terms of certain contractual agreements are recorded in restricted cash in the current assets section of our consolidated balance sheet. At September 30, 2018 and December 31, 2017, the Company had restricted cash of $25,000 and $370,000, respectively.
Accounts Receivable	Accounts Receivable Accounts receivable are reported net of the allowance for doubtful accounts. The allowance for doubtful accounts is determined based on a review of the Company’s receivables. Receivable accounts are charged off when collection efforts have failed or the account is deemed uncollectible. During 2016, the Company determined that a receivable account from a third-party natural gas and NGLs purchaser would no longer be collectible as a result of the third-party purchaser filing for bankruptcy. A summary of the activity related to the allowance for doubtful accounts is as follows: September 30, 2018 December 31, 2017 (in thousands) Allowance for doubtful accounts, beginning of period $ 1,953 $ 1,953 Expense — — Reductions/write-offs — — Allowance for doubtful accounts, end of period $ 1,953 $ 1,953
Recent Accounting Developments	Recent Accounting Developments Leases. In February 2016, the FASB issued updated guidance to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and enhance disclosures regarding key information about leasing arrangements. Under the new guidance, lessees will be required to recognize a lease liability and a right-of-use asset for all leases. The new lease guidance also simplified the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Additionally, in January 2018, the FASB issued an amendment to the updated guidance to permit an entity to elect an optional transition practical expedient to not evaluate under the new guidance land easements that exist or expire before the adoption of the updated guidance and that were not previously accounted for as leases under previous guidance. In July 2018, the FASB issued an additional amendment that permits an entity to elect an additional transition method to the existing modified retrospective transition requirements. Under the new transition method, an entity could adopt the provisions of this update by recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption without adjustment to the financial statements for periods prior to adoption. Consequently, an entity’s reporting for the comparative periods presented in the financial statements in which it adopts the new leases standard may continue to be in accordance with the previous lease guidance. This amendment also allows a practical expedient that permits lessors to not separate non-lease components from the associated lease component if certain conditions are present. The amendments in this update are effective beginning on January 1, 2019 and should be applied through a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early adoption is permitted. The Company has commenced analyzing its lease contracts but has not yet determined what the effects of adopting this updated guidance will be on its consolidated financial statements. The Company will adopt this updated guidance in the first quarter 2019 and anticipates that it will recognize a right of use asset and lease liability on the adoption date. The Company plans to apply practical expedients provided in the standards update that allow, among other things, not to reassess contracts that commenced prior to the adoption. The Company also anticipates electing a policy not to recognize right of use assets and lease liabilities related to short-term and immaterial leases. Revenue Recognition. On January 1, 2018, the Company adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“ASC 606”) using the modified retrospective method of transition. Under the modified retrospective approach, the standard has been applied to all existing contracts as of the date of initial application with the cumulative effect of applying the standard, if any, recognized in retained earnings. The impact of adoption on our current period results is as follows: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Under ASC 606 Under ASC 605 Increase (Decrease) Under ASC 606 Under ASC 605 Increase (Decrease) (in thousands) (in thousands) Revenues: Oil and condensate $ 17,436 $ 17,448 $ (12 ) $ 54,497 $ 54,530 $ (33 ) Natural gas 1,986 2,752 (766 ) 5,618 7,708 (2,090 ) NGLs 2,092 2,593 (501 ) 7,315 8,629 (1,314 ) Total oil and condensate, natural gas and NGLs revenues $ 21,514 $ 22,793 $ (1,279 ) $ 67,430 $ 70,867 $ (3,437 ) Expenses: Transportation, treating and gathering $ — $ 1,279 $ (1,279 ) $ — $ 3,437 $ (3,437 ) Net income (loss) $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ — Retained earnings $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ — The primary impact to our revenues as a result of the adoption of ASC 606 is the recording of transportation, treating, gathering and compression expenses (“Post-Production Expenses”) as a direct reduction to revenues instead of our historical practice of presenting such expenses gross in transportation, treating and gathering. These changes are due to the conclusion that the Company represents the agent in the sale of natural gas and NGLs under its gas processing and marketing agreements with midstream entities in accordance with the control model in ASC 606. As a result, the Company is required to record revenue on a net basis for amounts expected to be received from third-party customers through the marketing process, with Post-Production Expenses incurred subsequent to control of the product(s) transferring to the midstream entity at the wellhead being netted against revenue.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Summary of the activity related to the allowance for doubtful accounts	A summary of the activity related to the allowance for doubtful accounts is as follows: September 30, 2018 December 31, 2017 (in thousands) Allowance for doubtful accounts, beginning of period $ 1,953 $ 1,953 Expense — — Reductions/write-offs — — Allowance for doubtful accounts, end of period $ 1,953 $ 1,953
ASU 2014-09
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Schedule of Impact of Adoption	The impact of adoption on our current period results is as follows: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Under ASC 606 Under ASC 605 Increase (Decrease) Under ASC 606 Under ASC 605 Increase (Decrease) (in thousands) (in thousands) Revenues: Oil and condensate $ 17,436 $ 17,448 $ (12 ) $ 54,497 $ 54,530 $ (33 ) Natural gas 1,986 2,752 (766 ) 5,618 7,708 (2,090 ) NGLs 2,092 2,593 (501 ) 7,315 8,629 (1,314 ) Total oil and condensate, natural gas and NGLs revenues $ 21,514 $ 22,793 $ (1,279 ) $ 67,430 $ 70,867 $ (3,437 ) Expenses: Transportation, treating and gathering $ — $ 1,279 $ (1,279 ) $ — $ 3,437 $ (3,437 ) Net income (loss) $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ — Retained earnings $ 21,514 $ 21,514 $ — $ 67,430 $ 67,430 $ —

Property, Plant And Equipment (

Property, Plant And Equipment (Tables)	9 Months Ended
	Sep. 30, 2018
Business Acquisition [Line Items]
Schedule of Capitalized Costs of Unproved Properties Excluded from Amortization	The following table summarizes the components of unproved properties excluded from amortization at the dates indicated: September 30, 2018 December 31, 2017 (in thousands) Unproved properties, excluded from amortization: Drilling in progress costs $ 800 $ 4,772 Acreage acquisition costs 122,455 113,191 Capitalized interest 21,131 13,992 Total unproved properties excluded from amortization $ 144,386 $ 131,955
Schedule Of Relevant Assumptions Used In Ceiling Test Computations	The table below sets forth relevant pricing assumptions utilized in the quarterly ceiling test computations for the respective periods noted before adjustment for basis and quality differentials: 2018 Total Year to Date Impairment September 30 June 30 March 31 Henry Hub natural gas price (per MMBtu) (1) $ 2.91 $ 2.92 $ 3.00 WTI oil price (per Bbl) (1) $ 63.43 $ 57.67 $ 53.49 Impairment recorded (pre-tax) (in thousands) $ 17,993 $ — $ 17,993 $ — 2017 Total Year to Date Impairment September 30 June 30 March 31 Henry Hub natural gas price (per MMBtu) (1) $ 3.00 $ 3.01 $ 2.73 WTI oil price (per Bbl) (1) $ 49.81 $ 48.95 $ 47.61 Impairment recorded (pre-tax) (in thousands) $ — $ — $ — $ — (1) For the respective periods, oil and natural gas prices are calculated using the trailing 12-month unweighted arithmetic average of the first-day-of-the-month prices based on Henry Hub spot natural gas prices and WTI spot oil prices.
WEHLU
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information	As a result, certain estimates and judgments were made in preparing the pro forma adjustments. For the Three Months Ended September 30, 2017 (in thousands, except (Unaudited) Revenues $ 6,749 Net loss $ (19,133 ) Loss per share: Basic $ (0.09 ) Diluted $ (0.09 ) For the Nine Months Ended September 30 2018 2017 (in thousands, except (Unaudited) Revenues $ 42,983 $ 28,796 Net loss $ (81,973 ) $ (55,356 ) Loss per share: Basic $ (0.39 ) $ (0.26 ) Diluted $ (0.39 ) $ (0.26 )

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Summary of Reconciliation of Long-Term Debt Balance	The table below provides a reconciliation of the Company’s long-term debt balance as presented in the condensed consolidated balance sheets for the periods presented: September 30, 2018 December 31, 2017 (in thousands) Term Loan, principal balance (1) $ 276,778 $ 256,599 Less: Unamortized deferred financing costs (4,002 ) (4,724 ) Unamortized debt discount (19,873 ) (22,464 ) Term Loan, net $ 252,903 $ 229,411 Notes, principal balance $ 162,500 $ 162,500 Less: Unamortized deferred financing costs (2,217 ) (2,631 ) Unamortized debt discount (40,025 ) (46,328 ) Notes, net $ 120,258 $ 113,541 Total long-term debt $ 373,161 $ 342,952 (1) Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.
Summary of Carrying Amount of Equity Components of Notes Recorded in Additional Paid in Capital	The carrying amount of the equity components of the Notes recorded in additional paid in capital for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Value of conversion option $ 77,626 $ 77,626 Debt issuance costs attributable to conversion option $ (2,164 ) $ (2,164 ) Total $ 75,462 $ 75,462
Notes
Summary of Carrying Amounts of Long-Term debt	The carrying amount of the liability component of the Notes for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Notes, principal balance $ 162,500 $ 162,500 Less: Unamortized deferred financing costs (2,217 ) (2,631 ) Unamortized debt discount (40,025 ) (46,328 ) Notes, net $ 120,258 $ 113,541
Term Loan
Summary of Carrying Amounts of Long-Term debt	The carrying amounts of the Term Loan for the periods indicated are as follows: September 30, 2018 December 31, 2017 (in thousands) Term Loan, principal balance (1) $ 276,778 $ 256,599 Less: Unamortized deferred financing costs (4,002 ) (4,724 ) Unamortized debt discount (19,873 ) (22,464 ) Term loan, net $ 252,903 $ 229,411 (1) Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following tables set forth by level within the fair value hierarchy the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2018 and December 31, 2017: Fair value as of September 30, 2018 Level 1 Level 2 Level 3 Total (in thousands) Assets: Commodity derivative contracts $ — $ — $ — $ — Liabilities: Commodity derivative contracts — — (15,845 ) (15,845 ) Total $ — $ — $ (15,845 ) $ (15,845 ) Fair value as of December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Assets: Commodity derivative contracts $ — $ — $ 1,370 $ 1,370 Liabilities: Commodity derivative contracts — — (6,988 ) (6,988 ) Total $ — $ — $ (5,618 ) $ (5,618 )
Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation	The table below presents a reconciliation of the assets and liabilities classified as Level 3 in the fair value hierarchy for the three and nine months ended September 30, 2018 and 2017. Level 3 instruments presented in the table consist of net derivatives that, in management’s opinion, reflect the assumptions a marketplace participant would have used at September 30, 2018 and 2017. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) Balance at beginning of period $ (15,730 ) $ 9,436 $ (5,618 ) $ 7,512 Total (losses) gains included in earnings (2,925 ) (2,896 ) (17,710 ) 3,782 Purchases — — 552 470 Issuances — — — — Settlements (1) 2,810 (2,179 ) 6,931 (7,403 ) Balance at end of period $ (15,845 ) $ 4,361 $ (15,845 ) $ 4,361 The amount of total gains (losses) for the period included in earnings attributable to the change in mark to market of commodity derivatives contracts still held at September 30, 2018 and 2017 $ 433 $ (4,672 ) $ (9,026 ) $ (1,898 ) (1) Included in gain (loss) on commodity derivatives contracts on the condensed consolidated statements of operations.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Disaggregation of Revenues and Reconciliation of Total Revenues	The following represents a disaggregation of revenues and a reconciliation of total revenues as reported in the condensed consolidated statement of operations to revenue from contracts with customers: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 (1) 2018 2017 (1) (in thousands) Revenues Oil and condensate $ 17,436 $ 12,952 $ 54,497 $ 37,886 Natural gas 1,986 2,519 5,618 7,452 NGLs 2,092 2,757 7,315 7,527 Total revenues from contracts with customers $ 21,514 $ 18,228 $ 67,430 $ 52,865 (1) Prior period amounts have not been adjusted under the modified retrospective method.

Derivative Instruments and He_2

Derivative Instruments and Hedging Activity (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative [Line Items]
Summary of Information on the Location and Amounts of Commodity Derivative Fair Values and Commodity Derivative Gains and Losses	The tables below provide information on the location and amounts of derivative fair values in the condensed consolidated statement of financial position and derivative gains and losses in the condensed consolidated statement of operations for derivative instruments that are not designated as hedging instruments: Fair Values of Derivative Instruments Derivative Assets (Liabilities) Fair Value Balance Sheet Location September 30, 2018 December 31, 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts Current assets $ — $ 1,370 Commodity derivative contracts Current liabilities (13,211 ) (4,416 ) Commodity derivative contracts Long-term liabilities (2,634 ) (2,572 ) Total derivatives not designated as hedging instruments $ (15,845 ) $ (5,618 ) Amount of Gain (Loss) Recognized in Income on Derivatives For the Three Months Ended September 30, Location of (Loss) Gain Recognized in Income on Derivatives 2018 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts Loss on commodity derivatives contracts $ (2,925 ) $ (2,896 ) Total $ (2,925 ) $ (2,896 ) Amount of Gain (Loss) Recognized in Income on Derivatives For the Nine Months Ended September 30, Location of (Loss) Gain Recognized in Income on Derivatives 2018 2017 (in thousands) Derivatives not designated as hedging instruments Commodity derivative contracts (Loss) gain on commodity derivatives contracts $ (17,710 ) $ 3,782 Total $ (17,710 ) $ 3,782
Natural Gas
Derivative [Line Items]
Schedule of Notional Amounts and Weighted Average Underlying Hedge Prices of Outstanding Derivative Positions	As of September 30, 2018, the following natural gas derivative transactions were outstanding with the associated notional volumes and weighted average underlying hedge prices: Settlement Period Derivative Instrument Average Daily Volume Total of Notional Volume Base Fixed Price Floor (Long) Short Put Ceiling (Short) (in MMBtus) October to December 2018 Fixed price swap 1,550 142,600 $ 3.01 $ — $ — $ —
Crude Oil
Derivative [Line Items]
Schedule of Notional Amounts and Weighted Average Underlying Hedge Prices of Outstanding Derivative Positions	As of September 30, 2018, the following crude derivative transactions were outstanding with the associated notional volumes and weighted average underlying hedge prices: Settlement Period Derivative Instrument Average Daily Volume (1) Total of Notional Volume Base Fixed Price Floor (Long) Short Put Ceiling (Short) (in Bbls) October to December 2018 Costless three-way collar 1,700 156,400 $ — $ 47.50 $ 37.50 $ 57.85 October to December 2018 Fixed price swap 500 46,000 $ 61.60 $ — $ — $ — October to December 2018 Fixed price swap 600 55,200 $ 51.20 $ — $ — $ — January to September 2019 Costless three-way collar 2,000 546,000 $ — $ 47.50 $ 37.50 $ 59.70 October to December 2019 Costless three-way collar 1,900 174,800 $ — $ 47.50 $ 37.50 $ 59.70 January to September 2019 Fixed price swap 700 191,100 $ 50.40 $ — $ — $ — October to November 2019 Fixed price swap 600 36,600 $ 50.40 $ — $ — $ — December 2019 Fixed price swap 416 12,896 $ 50.40 $ — $ — $ — (1) Crude volumes hedged include oil, condensate and certain components of our NGLs production.

Capital Stock (Tables)

Capital Stock (Tables)	9 Months Ended
	Sep. 30, 2018
Stockholders Equity Note [Abstract]
Schedule of Issuances And Forfeitures Of Common Shares	The following table provides information regarding the issuances and forfeitures of common stock pursuant to the Company's long-term incentive plan for the periods indicated: For the Three Months Ended September 30, 2018 For the Nine Months Ended September 30, 2018 Other share issuances: Shares of restricted common stock granted — 3,231,531 Shares of restricted common stock vested 324,746 5,708,107 Shares of restricted common stock surrendered upon vesting/repurchase (1) 105,018 2,588,258 Shares of restricted common stock forfeited 137,089 584,187 _________________ (1) Represents shares of common stock forfeited in connection with the payment of estimated withholding taxes on shares of restricted common stock that vested during the period and vested shares of restricted stock repurchased from certain executives.

Interest Expense (Tables)

Interest Expense (Tables)	9 Months Ended
	Sep. 30, 2018
Interest Expense [Abstract]
Schedule Of Components Of Interest Expense	The following table summarizes the components of interest expense for the periods indicated: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) Interest expense: Cash and accrued $ 2,468 $ 2,438 $ 7,357 $ 19,644 Paid in kind 7,147 6,459 20,689 6,459 Amortization of deferred financing costs and debt discount 3,512 3,291 10,030 8,218 Capitalized interest (2,659 ) (2,029 ) (7,471 ) (4,577 ) Total interest expense $ 10,468 $ 10,159 $ 30,605 $ 29,744

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands, except per share and share data) Net loss attributable to common stockholders $ (21,145 ) $ (15,917 ) $ (79,714 ) $ (44,631 ) Weighted average common shares outstanding - basic 212,192,850 209,072,232 211,296,176 190,745,688 Weighted average common shares outstanding - diluted 212,192,850 209,072,232 211,296,176 190,745,688 Net loss per share of common stock attributable to common stockholders: Basic $ (0.10 ) $ (0.08 ) $ (0.38 ) $ (0.23 ) Diluted $ (0.10 ) $ (0.08 ) $ (0.38 ) $ (0.23 ) Common shares excluded from denominator as anti-dilutive: Unvested restricted shares 91,152 553,671 711,520 750,499 Unvested PBUs 888,888 1,654,841 204,742 713,911 Convertible notes 73,520,769 73,520,769 73,520,769 63,319,752 Total 74,500,809 75,729,281 74,437,031 64,784,162

Statement of Cash Flows - Sup_2

Statement of Cash Flows - Supplemental Information (Tables)	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Statement of Cash Flows Supplemental Information	The following is a summary of the supplemental cash paid and non-cash transactions for the periods indicated: For the Nine Months Ended September 30, 2018 2017 (in thousands) Cash paid for interest, net of capitalized amounts $ (114 ) $ 17,770 Non-cash transactions: Capital expenditures included in accounts payable and accrued drilling costs $ (4,496 ) $ 12,176 Capital expenditures included in accounts receivable $ — $ 76 Capital expenditures excluded from prepaid expenses $ (88 ) $ — Asset retirement obligation included in oil and natural gas properties $ 178 $ 403 Asset retirement obligation sold $ (2,581 ) $ (1,533 ) Application of advances to operators $ 920 $ 24 Non-cash financing charges excluded from accounts payable and accrued liabilities $ — $ 19 Undeclared cumulative dividends on preferred stock $ 3,618 $ 2,412 Conversion of convertible debt to equity $ — $ 37,500

Going Concern (Narrative) (Deta

Going Concern (Narrative) (Details)	Oct. 31, 2018	Oct. 26, 2018USD ($)Installment	Aug. 21, 2018Bid	Sep. 30, 2018
Going Concern [Line Items]
Number of bids received | Bid			3
Series A Cumulative Preferred Stock
Going Concern [Line Items]
Preferred stock, dividend rate, percentage (percentage)				8.625%
Series B Preferred Stock
Going Concern [Line Items]
Preferred stock, dividend rate, percentage (percentage)				10.75%
Subsequent Event
Going Concern [Line Items]
Petition date	Oct. 31, 2018
Subsequent Event | RSA
Going Concern [Line Items]
Pro rata percentage on new common equity		100.00%
Number of installments | Installment		2
Debtor-in-possession financing amount		$ 383,900,000
Subsequent Event | RSA | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing amount		100,000,000
Subsequent Event | RSA | Refinanced Term Loan
Going Concern [Line Items]
Debtor-in-possession financing amount		283,900,000
Subsequent Event | RSA | First Lien Exit Facility Term Loan
Going Concern [Line Items]
Principal balance		100,000,000
Subsequent Event | RSA | Second Lien Exit Facility Term Loan
Going Concern [Line Items]
Principal balance		$ 200,000,000
Subsequent Event | RSA | Exchange of Stock for Stock | Common Stock
Going Concern [Line Items]
Preferred holders, warrants to purchase percentage		2.50%
Equity holders, warrants to purchase percentage		2.50%
Subsequent Event | RSA | Interim DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, may be drawn		$ 15,000,000
Debtor-in-possession financing, may be drawn notice buiness days		3 days
Subsequent Event | RSA | Final DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, may be drawn		$ 100,000,000
Debtor-in-possession financing, may be drawn notice buiness days		3 days
Subsequent Event | RSA | Reserve DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, may be drawn		$ 100,000,000
Debtor-in-possession financing, may be drawn notice buiness days		3 days
Subsequent Event | RSA | Series A Cumulative Preferred Stock
Going Concern [Line Items]
Preferred stock, dividend rate, percentage (percentage)		8.625%
Subsequent Event | RSA | Series B Preferred Stock
Going Concern [Line Items]
Preferred stock, dividend rate, percentage (percentage)		10.75%
Subsequent Event | RSA | Maximum
Going Concern [Line Items]
Remaining availability claims under second lien exit facility		$ 200,000,000
Pro rata percentage on new common equity		100.00%
Subsequent Event | RSA | Minimum | Interim DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, initial draw		$ 2,500,000
Debtor-in-possession financing, each subsequent draw		500,000
Subsequent Event | RSA | Minimum | Final DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, each draw		500,000
Subsequent Event | RSA | Minimum | Reserve DIP Tranche | New Money Loans
Going Concern [Line Items]
Debtor-in-possession financing, each draw		$ 500,000
Subsequent Event | RSA | New Money Loans
Going Concern [Line Items]
Pro rata percentage of common equity upon exceeds second lien exit facility		100.00%
Subsequent Event | RSA | New Money Loans | Maximum
Going Concern [Line Items]
Financial restructuring aggregate amount claims		$ 200,000,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Accounting Policies [Abstract]
Restricted cash	$ 25	$ 370	$ 370

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Schedule of Allowance for Doubtful Accounts) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts, beginning of period	$ 1,953	$ 1,953
Expense	0	0
Reductions/write-offs	0	0
Allowance for doubtful accounts, end of period	$ 1,953	$ 1,953

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Schedule of Impact of Adoption) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	$ 21,514	$ 18,228	[1]	$ 67,430	$ 52,865	[1]
Expenses:
Net income (loss)	21,514			67,430
Retained earnings	21,514			67,430
Oil And Condensate
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	17,436	12,952	[1]	54,497	37,886	[1]
Natural Gas
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	1,986	2,519	[1]	5,618	7,452	[1]
NGLs
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	2,092	2,757	[1]	7,315	7,527	[1]
Transportation, Treating and Gathering
Expenses:
Expenses	0	$ 436		0	$ 1,187
Under ASC 605 | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	22,793			70,867
Expenses:
Net income (loss)	21,514			67,430
Retained earnings	21,514			67,430
Under ASC 605 | Oil And Condensate | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	17,448			54,530
Under ASC 605 | Natural Gas | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	2,752			7,708
Under ASC 605 | NGLs | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	2,593			8,629
Under ASC 605 | Transportation, Treating and Gathering | ASU 2014-09
Expenses:
Expenses	1,279			3,437
Increase (Decrease) | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	(1,279)			(3,437)
Increase (Decrease) | Oil And Condensate | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	(12)			(33)
Increase (Decrease) | Natural Gas | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	(766)			(2,090)
Increase (Decrease) | NGLs | ASU 2014-09
REVENUES:
Total oil, condensate, natural gas and NGLs revenues	(501)			(1,314)
Increase (Decrease) | Transportation, Treating and Gathering | ASU 2014-09
Expenses:
Expenses	$ (1,279)			$ (3,437)
[1]	Prior period amounts have not been adjusted under the modified retrospective method.

Property, Plant and Equipment_2

Property, Plant and Equipment (Schedule of Capitalized Costs of Unproved Properties Excluded from Amortization) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Unproved properties, excluded from amortization:
Drilling in progress costs	$ 800	$ 4,772
Acreage acquisition costs	122,455	113,191
Capitalized interest	21,131	13,992
Total unproved properties excluded from amortization	$ 144,386	$ 131,955

Property, Plant and Equipment_3

Property, Plant and Equipment (Narrative) (Details)	Jan. 23, 2018USD ($)	Oct. 02, 2017USD ($)	Mar. 22, 2017USD ($)awell	Oct. 14, 2016awellTownshipTranche	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017well
Property, Plant and Equipment [Line Items]
PUD reserves | $					$ 0
Proceeds from sale of natural gas and oil properties | $					96,349,000	$ 28,798,000
Acquisition of oil and natural gas properties | $					$ 269,000	$ 54,462,000
STACK Leasehold Acquisition
Property, Plant and Equipment [Line Items]
Gross wells			66
Net wells			9.5
Net acres | a			5,670
Acquisition of oil and natural gas properties | $			$ 51,400,000
Sale Agreement
Property, Plant and Equipment [Line Items]
Consideration on sale of property | $	$ 107,500,000
Proceeds from sale of natural gas and oil properties | $		$ 97,600,000
Development Agreement
Property, Plant and Equipment [Line Items]
Number of wells completed							20
Number of wells completed, net							15.8
Development Agreement | Parent Company
Property, Plant and Equipment [Line Items]
Number of wells completed, net							3.2
Development Agreement | Oklahoma
Property, Plant and Equipment [Line Items]
Investor funding percentage on working interest portion of drilling and completion cost				90.00%
Investors percentage of Gastar's working interest in each new well				80.00%
Percentage of costs paid to obtain 20% working interest				10.00%
Percentage on working interest in each new well				20.00%
Number of tranches | Tranche				3
Number of wells in each tranche				20
Number of wells in Meramec formation				18
Number of wells in Osage formation				2
Percentage of internal rate of return one				15.00%
Percentage of working interest on achievement of 15% internal rate of return				60.00%
Percentage of internal rate of return two				20.00%
Percentage of working interest on achievement of 20% internal rate of return				90.00%
Description of working interest on achievement of internal rate of returns				With respect to each 20-well tranche, when the Investor has achieved an aggregate 15% internal rate of return for its investment in the tranche, Investor’s interest will be reduced from 80% to 40% of the Company’s original working interest and the Company’s working interest increases from 20% to 60% of the original working interest. When a tranche internal rate of return of 20% is achieved by the Investor, Investor’s working interest decreases to 10% and the Company’s working interest increases to 90% of the working interest originally owned by the Company.
Development Agreement | Oklahoma | Investor
Property, Plant and Equipment [Line Items]
Percentage of working interest on achievement of 15% internal rate of return				40.00%
Percentage of working interest on achievement of 20% internal rate of return				10.00%
Development Agreement | Oklahoma | Investor
Property, Plant and Equipment [Line Items]
Net acres | a				21,200
Number of townships covered | Township				3
Gross acres | a				32,900
Development Agreement | Oklahoma | Investor | Maximum
Property, Plant and Equipment [Line Items]
Number of operated wells				60
Revenues and Direct Operating Expenses | Sale Agreement
Property, Plant and Equipment [Line Items]
Adjustments related to revenues and direct operating expenses | $		$ 9,900,000
Discount Rate
Property, Plant and Equipment [Line Items]
Fair market value, discounted present rate					10
Discount Rate | Development Agreement | Investor
Property, Plant and Equipment [Line Items]
Fair market value, discounted present rate					15

Property, Plant and Equipment_4

Property, Plant and Equipment (Average Sales Price and Production Costs Per Unit of Production) (Details) $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2018USD ($)$ / MMBTU$ / bbl	Jun. 30, 2018USD ($)$ / MMBTU$ / bbl	Mar. 31, 2018USD ($)$ / MMBTU$ / bbl	Sep. 30, 2017USD ($)$ / MMBTU$ / bbl	Jun. 30, 2017USD ($)$ / MMBTU$ / bbl	Mar. 31, 2017USD ($)$ / MMBTU$ / bbl	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Impairment recorded (pre-tax) | $		$ 0	$ 17,993	$ 0	$ 0	$ 0	$ 0	$ 17,993	$ 0
Natural Gas Per Thousand Cubic Feet
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average price | $ / MMBTU	[1]	2.91	2.92	3	3	3.01	2.73
Crude Oil And N G L Per Barrel
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average price | $ / bbl	[1]	63.43	57.67	53.49	49.81	48.95	47.61
[1]	For the respective periods, oil and natural gas prices are calculated using the trailing 12-month unweighted arithmetic average of the first-day-of-the-month prices based on Henry Hub spot natural gas prices and WTI spot oil prices.

Property, Plant And Equipment_5

Property, Plant And Equipment (Schedule of Pro Forma Information) (Details) - WEHLU - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Revenues	$ 6,749	$ 42,983	$ 28,796
Net loss	$ (19,133)	$ (81,973)	$ (55,356)
Loss per share, Basic	$ (0.09)	$ (0.39)	$ (0.26)
Loss per share, Diluted	$ (0.09)	$ (0.39)	$ (0.26)

Long-Term Debt - Reconciliation

Long-Term Debt - Reconciliation of Long-Term Debt Balance (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017	Mar. 03, 2017
Line of Credit Facility [Line Items]
Total long-term debt		$ 373,161	$ 342,952
Notes
Line of Credit Facility [Line Items]
Principal balance		162,500	162,500
Unamortized deferred financing costs		(2,217)	(2,631)	$ (5,400)
Unamortized debt discount		(40,025)	(46,328)	(52,400)
Long term loan, net		120,258	113,541
Term Loan
Line of Credit Facility [Line Items]
Principal balance	[1],[2]	276,778	256,599
Unamortized deferred financing costs		(4,002)	(4,724)	(5,500)
Unamortized debt discount		(19,873)	(22,464)	$ (25,200)
Long term loan, net		$ 252,903	$ 229,411
[1]	Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.
[2]	Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Long-Term Debt - Reconciliati_2

Long-Term Debt - Reconciliation of Long-Term Debt Balance (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended		12 Months Ended	18 Months Ended
		Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 02, 2018	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Kind interest due, amount			$ 20,179	$ 0
Term Loan
Line of Credit Facility [Line Items]
Principal balance	[1],[2]	$ 276,778	$ 276,778				$ 256,599
Term Loan | Amendment No. 2
Line of Credit Facility [Line Items]
Percentage of interest pay in kind		100.00%			100.00%
Kind interest due, amount		$ 7,000			$ 26,800
Principal balance					$ 276,800
Term Loan | Amendment No. 2 | Scenario, Forecast
Line of Credit Facility [Line Items]
Percentage of interest pay in kind						100.00%
[1]	Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.
[2]	Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)

Aug. 02, 2017

May 05, 2017

May 02, 2017

Mar. 03, 2017

Feb. 15, 2017

Sep. 30, 2018

Sep. 30, 2018

Sep. 30, 2017

Jul. 02, 2018

Dec. 31, 2016

Jun. 29, 2018

Dec. 31, 2017

Jun. 30, 2017

May 04, 2017

Apr. 30, 2017

Mar. 21, 2017

Jan. 10, 2017

Line of Credit Facility [Line Items]

Proceeds from issuance of common stock, net of issuance costs

$ 0

$ 56,366,000

Common stock volume weighted average trading price per share

$ 1.7002

Revolving Credit Facility

Line of Credit Facility [Line Items]

Repayment of debt

$ 69,200,000

Series A Preferred Stock

Line of Credit Facility [Line Items]

Preferred stock, par value

$ 0.01

$ 0.01

$ 0.01

Dividends payable, date declared, month and year

2018-06

Series B Preferred Stock

Line of Credit Facility [Line Items]

Preferred stock, par value

$ 0.01

$ 0.01

$ 0.01

Dividends payable, date declared, month and year

2018-06

Notes

Line of Credit Facility [Line Items]

Aggregate principal amount

$ 162,500,000

$ 162,500,000

$ 162,500,000

Term loan amount

$ 120,258,000

$ 120,258,000

113,541,000

Interest rate

6.00%

6.00%

Debt instrument maturity date

Mar. 1, 2022

Debt instrument fair value

147,800,000

Debt discount

52,400,000

$ 40,025,000

$ 40,025,000

46,328,000

Debt issuance costs

5,400,000

2,217,000

$ 2,217,000

2,631,000

Debt instrument, default, description

The Indenture provides that a number of events will constitute an Event of Default (as defined in the Indenture), including, among other things: (i) a failure to pay the Notes when due at maturity, upon redemption or repurchase; (ii) failure to pay interest for 30 days; (iii) the Company’s failure to deliver certain notices; (iv) a default in the Company’s obligation to convert the Notes; (v) the Company’s failure to comply with certain covenants relating to merger, consolidation or sale of assets; (vi) the Company’s failure to comply, for 60 days following notice, with any of the other covenants or agreements in the Indenture; (vii) a default, which is not cured within 30 days, by the Company or any Restricted Subsidiaries (as defined in the Indenture) with respect to any mortgages or any indebtedness for money borrowed of at least $15 million; (viii) one or more final judgments against the Company or any of its Restricted Subsidiaries for the payment of at least $15 million; (ix) the Company’s failure to make any payments required under that certain development agreement, which is not cured within 30 days; (x) causing any Guarantee (as defined in the Indenture) to cease to be in full force and effect; (xi) the cessation to be in full force and effect of any of the collateral agreements entered into with respect to the Notes; and (xii) certain events of bankruptcy or insolvency.

Debt instrument, debt default, amount

$ 15,000,000

$ 15,000,000

Aggregate principal amount of the then outstanding notes, percentage

25.00%

25.00%

Value of conversion option

77,600,000

$ 77,626,000

$ 77,626,000

77,626,000

Debt issuance costs related to liability component notes

3,200,000

Debt issuance costs related to equity component notes

$ 2,200,000

2,164,000

$ 2,164,000

2,164,000

Amortization of debt issuance costs percentage

16.00%

Senior Secured Notes Due 2018

Line of Credit Facility [Line Items]

Aggregate principal amount

$ 325,000,000

Interest rate

8.625%

Debt instrument redemption price percentage

102.156%

Redemption date

Mar. 24, 2017

Debt instrument maturity date

May 15, 2018

Additional amount paid on redemption over principle

$ 7,000,000

Wrote-off of remaining unamortized deferred financing costs

$ 5,200,000

Amendment No. 4 | Series A Preferred Stock

Line of Credit Facility [Line Items]

Dividends payable, date declared, month and year

2018-06

Amendment No. 4 | Series B Preferred Stock

Line of Credit Facility [Line Items]

Dividends payable, date declared, month and year

2018-06

Second Supplemental Indenture | Series A Preferred Stock

Line of Credit Facility [Line Items]

Dividends payable, date declared, month and year

2018-06

Second Supplemental Indenture | Series B Preferred Stock

Line of Credit Facility [Line Items]

Dividends payable, date declared, month and year

2018-06

Second Amended and Restated Revolving Credit Facility

Line of Credit Facility [Line Items]

Revolving credit facility scheduled maturity date

Nov. 14, 2017

Amendment No. 10

Line of Credit Facility [Line Items]

Preferred dividends payment, minimum required cash liquidity

$ 30,000,000

Agreed additional indebtedness to pay down

$ 8,100,000

First Lien Secured Term Loan

Line of Credit Facility [Line Items]

Aggregate principal amount

[1],[2]

276,778,000

$ 276,778,000

256,599,000

Term loan amount

252,903,000

$ 252,903,000

229,411,000

Interest rate

8.50%

Frequency of interest payment

quarterly

Debt instrument maturity date

Mar. 3, 2022

Debt instrument fair value

$ 224,800,000

Debt discount

25,200,000

19,873,000

$ 19,873,000

22,464,000

Debt issuance costs

$ 5,500,000

$ 4,002,000

$ 4,002,000

$ 4,724,000

Debt instrument effective interest rate percentage

13.00%

First Lien Secured Term Loan | Amendment No. 2

Line of Credit Facility [Line Items]

Aggregate principal amount

$ 276,800,000

Interest rate

10.25%

8.50%

Debt instrument, payment terms

Amendment No. 2 amended the Term Loan, to among other things, (i) allow for the payment of pay in kind (“PIK”) interest on the Term Loan at the applicable PIK percentage and (ii) increased the applicable interest rate for periods ending after June 30, 2017 from 8.5% per annum to 10.25% per annum. Amendment No. 2 allows the Company to elect to PIK upon proper notice 100% of interest payments due after June 30, 2017 and prior to December 31, 2018 and at the Company’s election, PIK between 0% and 50% of any interest payments occurring after December 31, 2018 (other than interest due on the maturity date or the date of any repayment or prepayment).

Percentage of interest pay in kind

100.00%

100.00%

First Lien Secured Term Loan | Amendment No. 2 | June 30, 2017 to December 31, 2018

Line of Credit Facility [Line Items]

Percentage of interest pay in kind

100.00%

First Lien Secured Term Loan | Amendment No. 2 | Minimum | After December 31, 2018

Line of Credit Facility [Line Items]

Percentage of interest pay in kind

0.00%

First Lien Secured Term Loan | Amendment No. 2 | Maximum | After December 31, 2018

Line of Credit Facility [Line Items]

Percentage of interest pay in kind

50.00%

Securities Purchase Agreement | Common Stock

Line of Credit Facility [Line Items]

Issuance of common shares - cash, net of offering costs (shares)

25,456,521

Ares Management, LLC | Senior Secured Notes Due 2018

Line of Credit Facility [Line Items]

Aggregate principal amount

$ 325,000,000

$ 325,000,000

Ares Management, LLC | Securities Purchase Agreement

Line of Credit Facility [Line Items]

Aggregate principal amount

$ 75,000,000

Common stock volume weighted average trading price per share

$ 1.7002

Number of consecutive trading days used in volume-weighted average trading price

30 days

Interest rate

8.625%

Debt instrument redemption price percentage

102.156%

Redemption date

Mar. 24, 2017

Aggregate principal amount, exchanged

$ 37,500,000

Repurchase share, issued

$ 1.4731

Aggregate principle amount of issued and outstanding notes

$ 162,500,000

$ 200,000,000

Ares Management, LLC | Securities Purchase Agreement | Common Stock

Line of Credit Facility [Line Items]

Issuance of common shares - cash, net of offering costs (shares)

25,456,521

29,408,305

Proceeds from issuance of common stock, net of issuance costs

$ 50,000,000

Ares Management, LLC | Securities Purchase Agreement | Special Voting Preferred Stock

Line of Credit Facility [Line Items]

Issuance of common shares - cash, net of offering costs (shares)

2,000

Preferred stock, par value

$ 0.01

Ares Management, LLC | Securities Purchase Agreement | Notes

Line of Credit Facility [Line Items]

Aggregate principal amount

125,000,000

Ares Management, LLC | Securities Purchase Agreement | Senior Secured Notes Due 2018

Line of Credit Facility [Line Items]

Repayment of debt

325,000,000

Ares Management, LLC | Securities Purchase Agreement | First Lien Secured Term Loan

Line of Credit Facility [Line Items]

Term loan amount

$ 250,000,000

[1]

Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

[2]

Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Long-Term Debt - Summary of Car

Long-Term Debt - Summary of Carrying Amounts of Term Loan (Details) - Term Loan - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017	Mar. 03, 2017
Line of Credit Facility [Line Items]
Principal balance	[1],[2]	$ 276,778	$ 256,599
Unamortized deferred financing costs		(4,002)	(4,724)	$ (5,500)
Unamortized debt discount		(19,873)	(22,464)	$ (25,200)
Long term loan, net		$ 252,903	$ 229,411
[1]	Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.
[2]	Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Long-Term Debt - Summary of C_2

Long-Term Debt - Summary of Carrying Amounts of Term Loan (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended		12 Months Ended	18 Months Ended
		Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 02, 2018	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Kind interest due, amount			$ 20,179	$ 0
Term Loan
Line of Credit Facility [Line Items]
Principal balance	[1],[2]	$ 276,778	$ 276,778				$ 256,599
Term Loan | Amendment No. 2
Line of Credit Facility [Line Items]
Percentage of interest pay in kind		100.00%			100.00%
Kind interest due, amount		$ 7,000			$ 26,800
Principal balance					$ 276,800
Term Loan | Amendment No. 2 | Scenario, Forecast
Line of Credit Facility [Line Items]
Percentage of interest pay in kind						100.00%
[1]	Pursuant to Amendment No. 2 (as defined below), the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.
[2]	Pursuant to Amendment No. 2, the Company can elect to pay in kind 100% of the interest due after June 30, 2017 to December 31, 2018. The Company elected to pay in kind 100% of the interest due for the period June 30, 2017 to July 2, 2018 in the amount of $26.8 million, thus increasing the outstanding principal balance of the Term Loan to $276.8 million. The Company elected to pay in kind 100% of the interest due for the period July 2, 2018 to September 30, 2018 in the amount of $7.0 million and such was accrued at September 30, 2018 due to the interest payment date falling on a weekend outside of quarter end.

Long-Term Debt - Summary of C_3

Long-Term Debt - Summary of Carrying Amount of Liability Component of Notes (Details) - Notes - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Mar. 03, 2017
Line of Credit Facility [Line Items]
Principal balance	$ 162,500	$ 162,500
Unamortized deferred financing costs	(2,217)	(2,631)	$ (5,400)
Unamortized debt discount	(40,025)	(46,328)	$ (52,400)
Long term loan, net	$ 120,258	$ 113,541

Long-Term Debt - Summary of C_4

Long-Term Debt - Summary of Carrying Amount of Equity Components of Notes Recorded in Additional Paid in Capital (Details) - Notes - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Mar. 03, 2017
Line of Credit Facility [Line Items]
Value of conversion option	$ 77,626	$ 77,626	$ 77,600
Debt issuance costs attributable to conversion option	(2,164)	(2,164)	$ (2,200)
Fair value of conversion option, net	$ 75,462	$ 75,462

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurements, Recurring and Nonrecurring) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Assets, Commodity derivative contracts		$ 1,370
Liabilities:
Liabilities, Commodity derivative contracts	$ (15,845)	(6,988)
Total	(15,845)	(5,618)
Level 3
Assets:
Assets, Commodity derivative contracts		1,370
Liabilities:
Liabilities, Commodity derivative contracts	(15,845)	(6,988)
Total	$ (15,845)	$ (5,618)

Fair Value Measurements (Net Ch

Fair Value Measurements (Net Change in Assets and Liabilities Measured at Fair Value on a Recurring Basis and Included in the Level 3 Fair Value Category) (Details) - Fair Value, Measurements, Recurring - Level 3 - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		$ (15,730)	$ 9,436	$ (5,618)	$ 7,512
Total (losses) gains included in earnings		(2,925)	(2,896)	(17,710)	3,782
Purchases				552	470
Settlements	[1]	2,810	(2,179)	6,931	(7,403)
Balance at end of period		(15,845)	4,361	(15,845)	4,361
The amount of total gains (losses) for the period included in earnings attributable to the change in mark to market of commodity derivatives contracts still held at September 30, 2018 and 2017		$ 433	$ (4,672)	$ (9,026)	$ (1,898)
[1]	Included in gain (loss) on commodity derivatives contracts on the condensed consolidated statements of operations.

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - Level 2 $ in Millions	Sep. 30, 2018USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of notes excluding conversion feature	$ 113.1
Fair value of term loan	$ 241

Revenue from Contract with Cust

Revenue from Contract with Customers (Disaggregation of Revenues and Reconciliation of Total Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Revenues
Total revenues from contracts with customers	$ 21,514	$ 18,228		$ 67,430	$ 52,865
Oil and Condensate
Revenues
Total revenues from contracts with customers	17,436	12,952		54,497	37,886
Natural Gas
Revenues
Total revenues from contracts with customers	1,986	2,519		5,618	7,452
NGLs
Revenues
Total revenues from contracts with customers	$ 2,092	$ 2,757		$ 7,315	$ 7,527
[1]	Prior period amounts have not been adjusted under the modified retrospective method.

Revenue from Contract with Cu_2

Revenue from Contract with Customers (Narrative) (Details)	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Significant judgments	Principal versus Agent The Company engages in various types of transactions in which midstream entities process its wet gas and, in some scenarios, subsequently market resulting NGLs and residue gas to third-party customers on the Company’s behalf, such as gas processing contracts. These types of transactions require judgment to determine whether the Company is the principal or the agent in the contract and, as a result, whether revenues are recorded gross or net. For the Company’s existing contracts, the Company has determined that it represents the agent in the sale of products under certain gas processing and marketing agreements with midstream entities in accordance with the control model in ASC 606. As a result, the Company presents revenue on a net basis for amounts expected to be received from third-party customers through the marketing process, with Post-Production Expenses incurred subsequent to control of the product(s) transferring to the midstream entity being netted against revenue.
Revenue, practical expedient, nondisclosure of transaction price allocation to remaining performance obligation	true
Performance obligation, description of timing	The Company records revenue in the month its production is delivered to the purchaser. However, settlement statements and payment may not be received for 30 to 90 days after the date production is delivered, and as a result, the Company is required to estimate the amount of production that was delivered to the purchaser and the price that will be received for the sale of the product including any transportation and other deductions.

Derivative Instruments and He_3

Derivative Instruments and Hedging Activity (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Nov. 01, 2018
Derivative [Line Items]
Gain (loss) related to change in fair value of commodity derivative contracts	$ 433,000	$ (4,700,000)	$ (9,000,000)	$ (1,900,000)
Gain (loss) for the settlement of derivatives	(3,400,000)	$ 1,800,000	$ (8,700,000)	$ 5,700,000
Hedge Party Restructuring Support Agreement | Secured Notes
Derivative [Line Items]
Current hedge positions termination date			Nov. 1, 2018
Derivative maturity date			Dec. 31, 2019
Derivative instrument accrued interest	$ 0		$ 0
Hedge Party Restructuring Support Agreement | Secured Notes | Subsequent Event
Derivative [Line Items]
Hedged liability, secured note value					$ 12,400,000

Derivative Instruments and He_4

Derivative Instruments and Hedging Activity (Schedule of Notional Amounts and Weighted Average Underlying Hedge Prices of Outstanding Derivative Positions) (Details)	9 Months Ended
	Sep. 30, 2018MMBTU$ / MMBTU$ / bblbbl
Fixed Price Swap - October to December 2018 | Natural Gas
Derivative [Line Items]
Base Fixed Price (Price per MMBtu or Bbl) | $ / MMBTU	3.01
Average Daily Volume (MMBtu or Bbl) | MMBTU	1,550
Total of Notional Volume (MMBtu) | MMBTU	142,600
Crude Oil | Costless Three-Way Collar - October to December 2018
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	1,700	[1]
Total of Notional Volume (Bbl)	156,400
Crude Oil | Costless Three-Way Collar - October to December 2018 | Long
Derivative [Line Items]
Floor (Long) (Price per MMBtu or Bbl) | $ / bbl	47.50
Crude Oil | Costless Three-Way Collar - October to December 2018 | Short
Derivative [Line Items]
Put (Short) (Price per MMBtu or Bbl) | $ / bbl	37.50
Ceiling (Short) (Price per MMBtu or Bbl) | $ / bbl	57.85
Crude Oil | Fixed Price Swap One - October to December 2018
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	500	[1]
Total of Notional Volume (Bbl)	46,000
Base Fixed Price (Price per MMBtu or Bbl) | $ / bbl	61.60
Crude Oil | Fixed Price Swap Two - October to December 2018
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	600	[1]
Total of Notional Volume (Bbl)	55,200
Base Fixed Price (Price per MMBtu or Bbl) | $ / bbl	51.20
Crude Oil | Costless Three-Way Collar - January to September 2019
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	2,000	[1]
Total of Notional Volume (Bbl)	546,000
Crude Oil | Costless Three-Way Collar - January to September 2019 | Long
Derivative [Line Items]
Floor (Long) (Price per MMBtu or Bbl) | $ / bbl	47.50
Crude Oil | Costless Three-Way Collar - January to September 2019 | Short
Derivative [Line Items]
Put (Short) (Price per MMBtu or Bbl) | $ / bbl	37.50
Ceiling (Short) (Price per MMBtu or Bbl) | $ / bbl	59.70
Crude Oil | Costless Three-Way Collar - October to December 2019
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	1,900	[1]
Total of Notional Volume (Bbl)	174,800
Crude Oil | Costless Three-Way Collar - October to December 2019 | Long
Derivative [Line Items]
Floor (Long) (Price per MMBtu or Bbl) | $ / bbl	47.50
Crude Oil | Costless Three-Way Collar - October to December 2019 | Short
Derivative [Line Items]
Put (Short) (Price per MMBtu or Bbl) | $ / bbl	37.50
Ceiling (Short) (Price per MMBtu or Bbl) | $ / bbl	59.70
Crude Oil | Fixed Price Swap - January to September 2019
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	700	[1]
Total of Notional Volume (Bbl)	191,100
Base Fixed Price (Price per MMBtu or Bbl) | $ / bbl	50.40
Crude Oil | Fixed Price Swap - October to November 2019
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	600	[1]
Total of Notional Volume (Bbl)	36,600
Base Fixed Price (Price per MMBtu or Bbl) | $ / bbl	50.40
Crude Oil | Fixed Price Swap - December 2019
Derivative [Line Items]
Average Daily Volume (MMBtu or Bbl)	416	[1]
Total of Notional Volume (Bbl)	12,896
Base Fixed Price (Price per MMBtu or Bbl) | $ / bbl	50.40
[1]	Crude volumes hedged include oil, condensate and certain components of our NGLs production.

Derivative Instruments and He_5

Derivative Instruments and Hedging Activity (Summary of Information on the Location and Amounts of Derivative Fair Values and Derivative Gains and Losses) (Details) - Commodity Contract - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
(Loss) gain on commodity derivatives contracts	$ (2,925)	$ (2,896)	$ (17,710)	$ 3,782
Gain (loss) on commodity derivatives contracts
Derivatives, Fair Value [Line Items]
(Loss) gain on commodity derivatives contracts	(2,925)	$ (2,896)	(17,710)	$ 3,782
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Total	(15,845)		(15,845)		$ (5,618)
Derivatives not designated as hedging instruments | Current assets
Derivatives, Fair Value [Line Items]
Commodity derivative contracts, Assets					1,370
Derivatives not designated as hedging instruments | Current liabilities
Derivatives, Fair Value [Line Items]
Commodity derivative contracts, Liabilities	(13,211)		(13,211)		(4,416)
Derivatives not designated as hedging instruments | Long-term liabilities
Derivatives, Fair Value [Line Items]
Commodity derivative contracts, Liabilities	$ (2,634)		$ (2,634)		$ (2,572)

Capital Stock (Narrative) (Deta

Capital Stock (Narrative) (Details) - USD ($)	Jun. 29, 2018	Apr. 30, 2018	May 05, 2017	May 02, 2017	Mar. 03, 2017	Feb. 15, 2017	Jan. 31, 2017	Mar. 09, 2016	Jan. 31, 2017	Apr. 30, 2016	Feb. 20, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jul. 24, 2017	Mar. 22, 2017	Mar. 21, 2017	Dec. 31, 2016	May 07, 2015
Class Of Stock [Line Items]
Aggregate offering price																					$ 50,000,000
Proceeds from issuance of common stock, net of issuance costs														$ 0	$ 56,366,000
Volume-weighted average trading price of the common shares					$ 1.7002
Common stock, shares authorized												800,000,000		800,000,000		800,000,000	800,000,000			550,000,000
Common stock shares issued												218,933,504		218,933,504		218,874,418
Common stock shares outstanding												218,933,504		218,933,504		218,874,418
Preferred stock, shares authorized												40,000,000		40,000,000		40,000,000
Cash dividends on preferred stock														$ 13,267,000	19,298,000
Undeclared cumulative dividends on preferred stock												$ 3,618,000	$ 2,412,000	3,618,000	2,412,000
Dividends on preferred stock												$ 0	1,206,000	$ 7,236,000	8,443,000
Preferred stock dividends payment conditions applied commencement period								2016-04
Stock options
Class Of Stock [Line Items]
Common stock shares outstanding												127,400		127,400
PBUs
Class Of Stock [Line Items]
Common stock shares outstanding												888,888		888,888
2006 Long-Term Stock Incentive Plan
Class Of Stock [Line Items]
Shares reserved for issuance under LTIP				14,000,000
Shares available for future issuance (no more than) (shares)												7,953,365		7,953,365
Series A Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares authorized												10,000,000		10,000,000		10,000,000
Preferred stock, dividend rate, percentage (percentage)														8.625%
Preferred stock, par value												$ 0.01		$ 0.01		$ 0.01
Redemption price												$ 25		$ 25		$ 25
Preferred stock, shares issued												4,045,000		4,045,000		4,045,000
Preferred stock, shares outstanding												4,045,000		4,045,000		4,045,000
Preferred stock redemption price per share												$ 25		$ 25
Dividends payable, date declared														Apr. 9, 2018
Dividends payable, date paid	Jul. 2, 2018													Apr. 30, 2018
Dividends payable record date														Apr. 20, 2018
Cash dividends on preferred stock		$ 6,500,000											727,000	$ 8,000,000	11,600,000
Dividends payable, date declared, month and year	2018-06
Fixed rate preferred dividend increases percentage if suspension more than one year														2.00%
Undeclared cumulative dividends on preferred stock												$ 2,200,000	1,500,000	$ 2,200,000	1,500,000
Dividends on preferred stock														4,400,000	5,100,000
Undeclared dividends paid														3,600,000	6,500,000
Accumulated and unpaid dividends on preferred stock transferred to liquidation preference												$ 2,200,000		$ 2,200,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares authorized												10,000,000		10,000,000		10,000,000
Preferred stock, dividend rate, percentage (percentage)														10.75%
Preferred stock, par value												$ 0.01		$ 0.01		$ 0.01
Redemption price												$ 25		$ 25		$ 25
Preferred stock, shares issued												2,140,000		2,140,000		2,140,000
Preferred stock, shares outstanding												2,140,000		2,140,000		2,140,000
Preferred stock redemption price per share												$ 25		$ 25
Dividends payable, date declared														Apr. 9, 2018
Dividends payable, date paid	Jul. 2, 2018													Apr. 30, 2018
Dividends payable record date														Apr. 20, 2018
Cash dividends on preferred stock		$ 4,300,000							$ 4,800,000			$ 479,000		$ 5,300,000	7,700,000
Dividends payable, date declared, month and year	2018-06
Fixed rate preferred dividend increases percentage if suspension more than one year														2.00%
Undeclared cumulative dividends on preferred stock												1,400,000	$ 959,000	$ 1,400,000	959,000
Dividends on preferred stock														2,900,000	3,400,000
Undeclared dividends paid														2,400,000	$ 4,400,000
Accumulated and unpaid dividends on preferred stock transferred to liquidation preference												$ 1,400,000		$ 1,400,000
Period after change in control to redeem preferred stock														90 days
Option to convert shares of Series B Preferred Stock												$ 11.5207		$ 11.5207
Dividend declared or paid										$ 0
Special Voting Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares authorized																		2,000
Redemption price																		$ 0.01
Convertible Notes due 2022
Class Of Stock [Line Items]
Aggregate principal amount												$ 162,500,000		$ 162,500,000		$ 162,500,000
Amendment No. 10 | Series A Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date declared														Jan. 10, 2017
Dividends payable, date paid														Jan. 31, 2017
Dividends payable record date														Jan. 20, 2017
Cash dividends on preferred stock							$ 7,300,000
Amendment No. 10 | Series B Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date declared														Jan. 10, 2017
Dividends payable record date														Jan. 20, 2017
Dividend payable date														Jan. 31, 2017
Amendment No. 4 | Series A Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date paid	Jul. 2, 2018
Dividends payable, date declared, month and year	2018-06
Amendment No. 4 | Series B Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date paid	Jul. 2, 2018
Dividends payable, date declared, month and year	2018-06
Second Supplemental Indenture | Series A Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date paid	Jul. 2, 2018
Dividends payable, date declared, month and year	2018-06
Second Supplemental Indenture | Series B Preferred Stock
Class Of Stock [Line Items]
Dividends payable, date paid	Jul. 2, 2018
Dividends payable, date declared, month and year	2018-06
Securities Purchase Agreement | Additional Notes
Class Of Stock [Line Items]
Aggregate principal amount																			$ 75,000,000
Aggregate principal amount, exchanged			$ 37,500,000
Securities Purchase Agreement | Common Stock
Class Of Stock [Line Items]
Issuance of common shares - cash, net of offering costs (shares)			25,456,521
Ares Management, LLC | Securities Purchase Agreement
Class Of Stock [Line Items]
Aggregate principal amount																			$ 75,000,000
Number of consecutive trading days used in volume-weighted average trading price						30 days
Volume-weighted average trading price of the common shares						$ 1.7002
Aggregate principal amount, exchanged				$ 37,500,000
Ares Management, LLC | Securities Purchase Agreement | Convertible Notes due 2022
Class Of Stock [Line Items]
Aggregate principal amount					$ 125,000,000
Ares Management, LLC | Securities Purchase Agreement | Common Stock
Class Of Stock [Line Items]
Issuance of common shares - cash, net of offering costs (shares)				25,456,521	29,408,305
Proceeds from issuance of common stock, net of issuance costs					$ 50,000,000
Sales price of underwritten public offering before offering costs and expenses					$ 50,000,000
ATM Program
Class Of Stock [Line Items]
Issuance of common shares - cash, net of offering costs (shares)											5,447,919
Proceeds from issuance of common stock, net of issuance costs											$ 8,300,000
Expiration date														Feb. 24, 2017

Capital Stock (Schedule of Issu

Capital Stock (Schedule of Issuances and Forfeitures of Common Shares) (Details) - Restricted shares - shares		3 Months Ended	9 Months Ended
		Sep. 30, 2018	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of restricted common stock granted			3,231,531
Shares of restricted common stock vested		324,746	5,708,107
Shares of restricted common stock surrendered upon vesting/repurchase	[1]	105,018	2,588,258
Shares of restricted common stock forfeited		137,089	584,187
[1]	Represents shares of common stock forfeited in connection with the payment of estimated withholding taxes on shares of restricted common stock that vested during the period and vested shares of restricted stock repurchased from certain executives.

Interest Expense (Schedule of C

Interest Expense (Schedule of Components of Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest Expense [Abstract]
Cash and accrued	$ 2,468	$ 2,438	$ 7,357	$ 19,644
Paid in kind	7,147	6,459	20,689	6,459
Amortization of deferred financing costs and debt discount	3,512	3,291	10,030	8,218
Capitalized interest	(2,659)	(2,029)	(7,471)	(4,577)
Total interest expense	$ 10,468	$ 10,159	$ 30,605	$ 29,744

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Current income tax benefit or provision	$ 0	$ 0	$ 0	$ 0
Deferred income tax expense (benefit)	$ 0	$ 0	$ 0	$ 0

Earnings per Share (Schedule of

Earnings per Share (Schedule of Earnings per Share, Basic and Diluted, by Common Class, Including Two Class Method) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (21,145)	$ (15,917)	$ (79,714)	$ (44,631)
Weighted average common shares outstanding basic (shares)	212,192,850	209,072,232	211,296,176	190,745,688
Weighted average common shares outstanding diluted (shares)	212,192,850	209,072,232	211,296,176	190,745,688
Basic (dollars per share)	$ (0.10)	$ (0.08)	$ (0.38)	$ (0.23)
Diluted (dollars per share)	$ (0.10)	$ (0.08)	$ (0.38)	$ (0.23)
Common shares excluded from denominator as anti-dilutive (shares)	74,500,809	75,729,281	74,437,031	64,784,162
Unvested restricted shares
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Common shares excluded from denominator as anti-dilutive (shares)	91,152	553,671	711,520	750,499
Unvested PBUs
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Common shares excluded from denominator as anti-dilutive (shares)	888,888	1,654,841	204,742	713,911
Convertible notes
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Common shares excluded from denominator as anti-dilutive (shares)	73,520,769	73,520,769	73,520,769	63,319,752

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details)	Oct. 25, 2018	Aug. 31, 2018	May 03, 2016Officer	Sep. 30, 2018	Dec. 29, 2015USD ($)	Apr. 22, 2014awell
Executive
Loss Contingencies [Line Items]
Retention bonus, terms				On August 31, 2018, the Company, on the one hand, and each of Stephen P. Roberts, Michael A. Gerlich and Jerry R. Schuyler entered into retention bonus letters (each a “Retention Bonus Letter”) providing that each such executive will receive a cash payment (“Retention Bonus”), representing a certain percentage of his base salary, paid in a lump sum in cash on or before August 17, 2018. In the event the executive’s employment is terminated (i) by the Company for cause (as defined in the Retention Agreement) or (ii) due to his voluntarily resignation, the executive will be required to repay to the Company 100% of the Retention Bonus (net of any taxes withheld from same) if such termination occurs before December 31, 2018 and 50% of the Retention Bonus (net of taxes withheld from same) if such termination occurs after December 31, 2018 and before July 1, 2019 (the “Repayment Obligation”). The Repayment Obligation will cease in the event that the Company fails to pay the executive’s base salary in accordance with the Company’s normal payroll practices and fails to correct any such failure within five (5) days of written notice from the executive or upon the occurrence of a change in control (as defined in the Retention Bonus Letters) of the Company. The Repayment Obligation set forth in Mr. Schuyler’s Retention Bonus Letter is reduced on a straight line basis from 100% (if termination occurs before September 1, 2018) to 0% (if termination occurs any time after June 1, 2019) for each additional month that he remains employed by the Company.
Retention bonus amendments, terms				On October 25, 2018, Gastar entered into amendments (the “Retention Bonus Amendments”) to the Retention Bonus Letters. The Retention Bonus Amendments amend each of the respective Retention Bonus Letters to specify that the definition of “Change in Control” therein does not include a change of control resulting from the acquisition of a controlling interest from the Chapter 11 Cases or an acquisition by Ares or its affiliates. In addition, the Retention Bonus Amendments with Mr. Gerlich and Mr. Roberts provide that 100% of the retention bonus is repayable by the employee if he terminates employment without Good Reason or if the Company terminates his employment with Cause (as such terms are defined in the Retention Bonus Letters) prior to February 28, 2019, and 50% of the retention bonus is payable by the employee if such a termination occurs between February 28, 2019 and April 30, 2019.
Executive | Termination Occurs Before December 31, 2018
Loss Contingencies [Line Items]
Percentage of retention bonus net of tax payable by employee due to termination		100.00%
Executive | Termination Occurs After December 31, 2018 and Before July 1, 2019
Loss Contingencies [Line Items]
Percentage of retention bonus net of tax payable by employee due to termination		50.00%
Executive | Termination Occurs Before September 1, 2018
Loss Contingencies [Line Items]
Repayment of retention bonus, percentage reduction on straight line basis		100.00%
Executive | Termination Occurs Any Time After June 1, 2019
Loss Contingencies [Line Items]
Repayment of retention bonus, percentage reduction on straight line basis		0.00%
Executive | Termination Occurs Prior to February 28, 2019 | Subsequent Event
Loss Contingencies [Line Items]
Percentage of retention bonus payble by employee	100.00%
Executive | Termination Occurs Between February 28, 2019 and April 30, 2019 | Subsequent Event
Loss Contingencies [Line Items]
Percentage of retention bonus payble by employee	50.00%
Gastar Exploration Inc V Christopher Mc Arthur | Maximum
Loss Contingencies [Line Items]
Damages sought in arbitration matter | $					$ 2,750,000
Torchlight Energy Resources, Inc., Torchlight Energy, Inc. v. Husky Ventures, Inc.
Loss Contingencies [Line Items]
Number of executive officers filed lawsuit | Officer			2
Loss contingency, actions taken by plaintiff				On August 17, 2016, plaintiffs nonsuited, without prejudice, their claims against the former chairman of the board.
Loss contingency, date of dismissal of plantiff claims				May 22, 2017
Loss Contingency, settled the breach-of-contract counterclaim				May 23, 2018
Eagle Natrium LLC In the Court of Common Pleas of Allegheny County Pennsylvania [Member]
Loss Contingencies [Line Items]
Number of wells completed | well						3
Area of gastar operator						16,000
Gross area for oil and gas lease adjacent to eagles facilitties						3,300

Statement of Cash Flows - Sup_3

Statement of Cash Flows - Supplemental Information (Schedule of Supplemental Cash Paid and Non-cash Transactions) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of capitalized amounts			$ (114)	$ 17,770
Non-cash transactions:
Capital expenditures included in accounts payable and accrued drilling costs			(4,496)	12,176
Capital expenditures included in accounts receivable				76
Capital expenditures excluded from prepaid expenses			(88)
Asset retirement obligation included in oil and natural gas properties			178	403
Asset retirement obligation sold			(2,581)	(1,533)
Application of advances to operators			920	24
Non-cash financing charges excluded from accounts payable and accrued liabilities				19
Undeclared cumulative dividends on preferred stock	$ 3,618	$ 2,412	$ 3,618	2,412
Conversion of convertible debt to equity				$ 37,500