Magnolia Oil & Gas (MGY) 10-Q 13 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 13, 2018
Entity Information [Line Items]
Entity Registrant Name	Magnolia Oil & Gas Corp
Entity Central Index Key	1,698,990
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	true
Entity Small Business	false
Entity Ex Transition Period	false
Class A
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		156,332,733
Class B
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		93,346,725

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 36,715
Accounts receivable	167,174
Accounts receivable - related party	0
Drilling advances	5,791
Other current assets	2,033
Total current assets	211,713
PROPERTY, PLANT AND EQUIPMENT
Oil and natural gas properties	3,081,740
Accumulated depreciation, depletion and amortization	(65,069)
Total property, plant and equipment, net	3,016,671
OTHER ASSETS
Deferred financing costs, net	11,321
Equity method investment, net	18,409
Intangibles, net	41,983
TOTAL ASSETS	3,300,097
CURRENT LIABILITIES:
Accounts payable and accrued liabilities	178,072
Derivative liability	0
Total current liabilities	178,072
LONG-TERM LIABILITIES:
Long-term debt, net	388,343
Asset retirement obligations, net of current	43,437
Long-term derivative liability	0
Deferred taxes, net	47,236
Other long term liabilities	0
Total long-term liabilities	479,016
COMMITMENTS AND CONTINGENCIES (Note 13)
STOCKHOLDERS’ EQUITY
Additional paid in capital	1,647,905
Retained earnings	3,120
Noncontrolling interest	991,959
PARENTS’ NET INVESTMENT	0
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	3,300,097
Predecessor
CURRENT ASSETS:
Cash and cash equivalents		$ 0
Accounts receivable		100,512
Accounts receivable - related party		13,692
Drilling advances		0
Other current assets		332
Total current assets		114,536
PROPERTY, PLANT AND EQUIPMENT
Oil and natural gas properties		1,731,696
Accumulated depreciation, depletion and amortization		(166,159)
Total property, plant and equipment, net		1,565,537
OTHER ASSETS
Deferred financing costs, net		0
Equity method investment, net		8,901
Intangibles, net		0
TOTAL ASSETS		1,688,974
CURRENT LIABILITIES:
Accounts payable and accrued liabilities		74,536
Derivative liability		6,764
Total current liabilities		81,300
LONG-TERM LIABILITIES:
Long-term debt, net		0
Asset retirement obligations, net of current		3,929
Long-term derivative liability		3,052
Deferred taxes, net		2,724
Other long term liabilities		131
Total long-term liabilities		9,836
COMMITMENTS AND CONTINGENCIES (Note 13)
STOCKHOLDERS’ EQUITY
Additional paid in capital		0
Retained earnings		0
Noncontrolling interest		0
PARENTS’ NET INVESTMENT		1,597,838
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY		1,688,974
Class A Common Stock
STOCKHOLDERS’ EQUITY
Common stock	16
Class A Common Stock | Predecessor
STOCKHOLDERS’ EQUITY
Common stock		0
Class B Common Stock
STOCKHOLDERS’ EQUITY
Common stock	$ 9
Class B Common Stock | Predecessor
STOCKHOLDERS’ EQUITY
Common stock		$ 0

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Jul. 31, 2018
Class A
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,300,000,000
Common stock, shares issued (in shares)	155,227,284
Common stock, shares outstanding (in shares)	155,227,284
Class B
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	225,000,000
Common stock, shares issued (in shares)	90,452,174
Common stock, shares outstanding (in shares)	90,452,174

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 30, 2018	Sep. 30, 2017
REVENUES:
Total revenues		$ 178,556
OPERATING EXPENSES
Lease operating expenses		11,016
Gathering, transportation and processing		5,746
Taxes other than income		9,351
Exploration expense		11,221
Asset retirement obligation accretion		391
Depreciation, depletion and amortization		67,478
General & administrative expenses		10,297
Transaction related costs		22,366
Total operating costs and expenses		137,866
OPERATING INCOME		40,690
OTHER INCOME (EXPENSE):
Income (loss) from equity method investee		309
Interest expense		(4,959)
Gain (loss) on derivatives, net		0
Other income (expense), net		(7,019)
Total other income (expense)		(11,669)
INCOME BEFORE INCOME TAXES		29,021
Income tax expense		3,538
NET INCOME		25,483
LESS: Net income attributable to noncontrolling interest		18,775
NET INCOME ATTRIBUTABLE TO CLASS A COMMON STOCK		$ 6,708
NET INCOME PER COMMON SHARE
Basic (in dollars per share)		$ 0.04
Diluted (in dollars per share)		$ 0.04
WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
Basic (in shares)		151,992
Diluted (in shares)		157,072
Predecessor
REVENUES:
Total revenues	$ 76,887		$ 86,615	$ 449,186	$ 278,216
OPERATING EXPENSES
Lease operating expenses	3,681		6,180	23,513	18,931
Gathering, transportation and processing	2,240		3,997	12,929	12,238
Taxes other than income	2,087		5,823	23,763	18,028
Exploration expense	40		77	492	383
Asset retirement obligation accretion	21		87	104	175
Depreciation, depletion and amortization	23,157		27,124	137,871	88,844
General & administrative expenses	1,701		4,960	12,710	13,224
Transaction related costs	0		0	0	0
Total operating costs and expenses	32,927		48,248	211,382	151,823
OPERATING INCOME	43,960		38,367	237,804	126,393
OTHER INCOME (EXPENSE):
Income (loss) from equity method investee	(345)		(84)	711	(85)
Interest expense	0		0	0	0
Gain (loss) on derivatives, net	3,865		(1,648)	(18,127)	1,041
Other income (expense), net	24		0	(50)	(20)
Total other income (expense)	3,544		(1,732)	(17,466)	936
INCOME BEFORE INCOME TAXES	47,504		36,635	220,338	127,329
Income tax expense	766		630	1,785	1,967
NET INCOME	46,738		36,005	218,553	125,362
LESS: Net income attributable to noncontrolling interest	0		0	0	0
NET INCOME ATTRIBUTABLE TO CLASS A COMMON STOCK	46,738		36,005	218,553	125,362
Oil revenues
REVENUES:
Total revenues		$ 143,202
Oil revenues | Predecessor
REVENUES:
Total revenues	68,487		72,706	399,124	240,778
Natural gas revenues
REVENUES:
Total revenues		14,201
Natural gas revenues | Predecessor
REVENUES:
Total revenues	3,646		6,925	22,135	19,436
Natural gas liquids revenues
REVENUES:
Total revenues		$ 21,153
Natural gas liquids revenues | Predecessor
REVENUES:
Total revenues	$ 4,754		$ 6,984	$ 27,927	$ 18,002

Combined Statement of Changes i

Combined Statement of Changes in Parents' Net Investment and Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Tranche I	Tranche II	Total Stockholders' Equity	Common StockClass A Common Stock	Common StockClass A Common StockTranche I	Common StockClass A Common StockTranche II	Common StockClass B Common Stock	Common StockClass B Common StockTranche I	Common StockClass B Common StockTranche II	Common StockClass F Common Stock	Additional Paid In Capital	Accumulated Deficit	Noncontrolling Interest
Balance at beginning of period (Predecessor) at Dec. 31, 2017	$ 1,597,838
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Parents’ contribution, net | Predecessor	62,641
Net income | Predecessor	218,553
Balance at end of period (Predecessor) at Jul. 30, 2018	1,879,032
Balance at end of period (in shares) at Jul. 30, 2018					3,052			0			16,250
Balance at end of period at Jul. 30, 2018	4,784			$ 4,784	$ 0			$ 0			$ 2	$ 8,370	$ (3,588)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Class A Common Stock released from possible redemption (in shares)					61,948
Class A Common Stock released from possible redemption	619,479			619,479	$ 6							619,473
Class A Common Stock redeemed (in shares)					(1)
Class A Common Stock redeemed	(9)			(9)								(9)
Conversion of Common Stock from Class F to Class A at closing of Business Combination (in shares)					16,250						(16,250)
Conversion of Common Stock from Class F to Class A at closing of Business Combination	0				$ 2						$ (2)
Common Stock issued as part of the Business Combination (in shares)					31,791			83,939
Common Stock issued as part of the Business Combination	1,423,484			391,029	$ 3			$ 9				391,017		1,032,455
Class A Common Stock issuance in private placement (in shares)					35,500
Class A Common Stock issuance in private placement	355,000			355,000	$ 4							354,996
Earnout consideration issued as part for the Business Combination	149,700			41,371								41,371		108,329
Non-compete consideration	44,400			44,400								44,400
Changes in ownership interest adjustment	0			206,966								206,966		(206,966)
Changes in deferred tax liability	(52,787)			(52,787)								(52,787)
Balance at end of period (in shares) at Jul. 31, 2018					148,540			83,939			0
Balance at end of period at Jul. 31, 2018	2,544,051			1,610,233	$ 15			$ 9			$ 0	1,613,797	(3,588)	933,818
Balance at beginning of period (Predecessor) at Jul. 30, 2018	1,879,032
Balance at beginning of period (in shares) at Jul. 30, 2018					3,052			0			16,250
Balance at beginning of period at Jul. 30, 2018	4,784			4,784	$ 0			$ 0			$ 2	8,370	(3,588)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25,483
Balance at end of period at Sep. 30, 2018	0
Balance at end of period (in shares) at Sep. 30, 2018					155,228			90,451			0
Balance at end of period at Sep. 30, 2018	2,643,009			1,651,050	$ 16			$ 9			$ 0	1,647,905	3,120	991,959
Balance at beginning of period (in shares) at Jul. 31, 2018					148,540			83,939			0
Balance at beginning of period at Jul. 31, 2018	2,544,051			1,610,233	$ 15			$ 9			$ 0	1,613,797	(3,588)	933,818
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of earnout share consideration (in shares)						1,244	1,244		3,256	3,256
Issuance of earnout share consideration		$ 0	$ 0			$ 0	$ 0		$ 0	$ 0
Common Stock issued as part of the Business Combination (in shares)					4,200
Common Stock issued as part of the Business Combination	58,212			58,212	$ 1							58,211
Net income	25,483			6,708									6,708	18,775
Changes in ownership interest adjustment	0			(39,366)								(39,366)		39,366
Changes in deferred tax liability	15,263			15,263								15,263
Balance at end of period at Sep. 30, 2018	0
Balance at end of period (in shares) at Sep. 30, 2018					155,228			90,451			0
Balance at end of period at Sep. 30, 2018	$ 2,643,009			$ 1,651,050	$ 16			$ 9			$ 0	$ 1,647,905	$ 3,120	$ 991,959

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	2 Months Ended	7 Months Ended	9 Months Ended
	Sep. 30, 2018	Jul. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 25,483
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	67,478
Asset retirement obligations accretion expense	391
Amortization of deferred financing costs	570
Non-cash interest expense	4,206
(Gain) loss on derivatives, net	0
Cash settlements of matured derivative contracts	0
Deferred taxes	3,493
Contingent consideration change in fair value	6,700
Other	(218)
Changes in assets and liabilities, net of amounts acquired:
Account receivable	(77,500)
Prepaid expenses and other assets	(282)
Accounts payable and accrued liabilities	60,312
Other assets and liabilities, net	45
Net cash provided by (used in) operating activities	90,678
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds withdrawn from Trust Account	656,078
Additions to oil and natural gas properties	(37,100)
Purchase of and contributions to equity method investment	0
Payment of Contingent Consideration	(26,000)
Net cash used in investing activities	(761,891)
CASH FLOW FROM FINANCING ACTIVITIES:
Parents’ contribution, net	0
Issuance of common stock	355,000
Proceeds from issuance of long term debt	400,000
Repayments of deferred underwriting compensation	(22,750)
Cash paid for debt issuance costs	(23,336)
Other financing activities	(1,009)
Net cash provided by financing activities	707,905
NET CHANGE IN CASH AND CASH EQUIVALENTS	36,692
CASH AND CASH EQUIVALENTS – Beginning of period	23
CASH AND CASH EQUIVALENTS – End of period	36,715	$ 23
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for income taxes	0
Cash paid for interest	350
Supplemental non-cash investing and financing activity
Accruals or liabilities for capital expenditures	45,242
Contingent Consideration issued in Business Combination	149,700
Non-Compete agreement	44,400
Equity issuances in connection with business combinations	1,481,695
EnerVest properties
Adjustments to reconcile net income to net cash provided by operating activities:
Contingent consideration change in fair value	(6,700)
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(1,219,217)
Other
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(135,652)
Predecessor
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		218,553	$ 125,362
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization		137,871	88,844
Asset retirement obligations accretion expense		104	175
Amortization of deferred financing costs		0	0
Non-cash interest expense		0	0
(Gain) loss on derivatives, net		18,127	(1,041)
Cash settlements of matured derivative contracts		(27,617)	52
Deferred taxes		324	1,119
Contingent consideration change in fair value		0	0
Other		(796)	(189)
Changes in assets and liabilities, net of amounts acquired:
Account receivable		(61,405)	(28,113)
Prepaid expenses and other assets		0	(624)
Accounts payable and accrued liabilities		36	7,539
Other assets and liabilities, net		(385)	0
Net cash provided by (used in) operating activities		284,812	193,124
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds withdrawn from Trust Account		0	0
Additions to oil and natural gas properties		(197,314)	(188,205)
Purchase of and contributions to equity method investment		0	(8,788)
Payment of Contingent Consideration		0	0
Net cash used in investing activities		(347,453)	(255,646)
CASH FLOW FROM FINANCING ACTIVITIES:
Parents’ contribution, net		62,641	62,522
Issuance of common stock		0	0
Proceeds from issuance of long term debt		0	0
Repayments of deferred underwriting compensation		0	0
Cash paid for debt issuance costs		0	0
Other financing activities		0	0
Net cash provided by financing activities		62,641	62,522
NET CHANGE IN CASH AND CASH EQUIVALENTS		0	0
CASH AND CASH EQUIVALENTS – Beginning of period	$ 0	0	0
CASH AND CASH EQUIVALENTS – End of period		0	0
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for income taxes		336	43
Cash paid for interest		0	0
Supplemental non-cash investing and financing activity
Accruals or liabilities for capital expenditures		38,028	54,968
Equity issuances in connection with business combinations		0	0
Predecessor | EnerVest properties
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions		0	0
Predecessor | Other
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions		$ (150,139)	$ (58,653)

Description of Business and Bas

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Organization and General Magnolia Oil & Gas Corporation (the “Company” or "Magnolia") was incorporated in Delaware on February 14, 2017 (“Inception”). The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act of 1933, as amended, as modified by the Jumpstart Our Business Startups Act of 2012. On March 15, 2018, the Company formed three indirect wholly owned subsidiaries; Magnolia Oil & Gas Parent LLC ("Magnolia LLC"), Magnolia Oil & Gas Intermediate LLC ("Magnolia Intermediate"), and Magnolia Oil & Gas Operating LLC ("Magnolia Operating"). All three entities are Delaware limited liability companies and were formed in contemplation of the Business Combination (as defined herein). Business Combination On July 31, 2018 (the “Closing Date”), the Company and Magnolia LLC, a consolidated subsidiary of the Company, consummated the previously announced acquisition of: • certain right, title and interest in certain oil and natural gas assets located primarily in the Karnes County portion of the Eagle Ford Shale in South Texas (the "Karnes County Assets" and, such business the “Karnes County Business”) pursuant to that certain Contribution and Merger Agreement (as subsequently amended, the “Karnes County Contribution Agreement”), by and among the Company, Magnolia LLC and certain affiliates (the “Karnes County Contributors”) of EnerVest Ltd. (“EnerVest”); • certain right, title and interest in certain oil and natural gas assets located primarily in the Giddings Field of the Austin Chalk (the "Giddings Assets") pursuant to that certain Purchase and Sale Agreement (the “Giddings Purchase Agreement”) by and among Magnolia LLC and certain affiliates of EnerVest (the “Giddings Sellers”); and • an approximately 35% membership interest (the “Ironwood Interests” and together with the Karnes County Assets and the Giddings Assets, the “Acquired Assets”) in Ironwood Eagle Ford Midstream, LLC ("Ironwood"), a Texas limited liability company, which owns an Eagle Ford gathering system, pursuant to that certain Membership Interest Purchase Agreement (the “Ironwood MIPA” and, together with the transactions contemplated by the Karnes County Contribution Agreement and the Giddings Purchase Agreement, the “Business Combination Agreements” and the transactions contemplated thereby, the “Business Combination”), by and among Magnolia LLC and certain affiliates of EnerVest (the “Ironwood Sellers”). The Company consummated the Business Combination for aggregate consideration of approximately $1.2 billion in cash, 31.8 million shares of the Company's Class A Common Stock, par value $0.0001 per share (the "Class A Common Stock"), and 83.9 million shares of the Company's Class B Common Stock, par value $0.0001 per share (the "Class B Common Stock") and a corresponding number of units in Magnolia LLC (the "Magnolia LLC Units"), as well as certain earnout rights payable in a combination of cash and additional equity securities in the Company. In connection with the Business Combination, Magnolia issued and sold 35.5 million shares of Class A Common Stock in a private placement to certain qualified institutional buyers and accredited investors for gross proceeds of $355.0 million (the “PIPE Investment”). In addition, Magnolia Operating and Magnolia Oil & Gas Finance Corp., a wholly owned subsidiary of Magnolia Operating ("Finance Corp." and, together with Magnolia Operating, the "Issuers"), issued and sold $400.0 million aggregate principal amount of 6.0% Senior Notes due 2026 (the “2026 Senior Notes”). The proceeds of the PIPE Investment and the offering of 2026 Notes were used to fund a portion of the cash consideration required to effect the Business Combination. Business Operations and Strategy Magnolia is an independent oil and natural gas company engaged in the acquisition, development, exploration and production of oil, natural gas and NGL reserves from the Eagle Ford Shale and Austin Chalk formations in South Texas. Magnolia's objective is to generate stock market value over the long term through consistent organic production growth, high full cycle operating margins, an efficient capital program with short economic paybacks, significant free cash flow after capital expenditures, and effective reinvestment of free cash flow. Basis of Presentation As a result of the Business Combination, the Company is the acquirer for accounting purposes and the Karnes County Business, the Giddings Assets, and the Ironwood Interests are the acquirees. The Karnes County Business, including as applicable, its ownership of the Ironwood Interests, was deemed the "Predecessor" for periods prior to the Business Combination, and does not include the consolidation of the Company and the Giddings Assets. The assets, liabilities, revenues, expenses and cash flows related to the Karnes County Business were not previously separately accounted for as a standalone legal entity and have been carved out of the overall assets, liabilities, revenues, expenses and cash flows from the Karnes County Contributors as appropriate. For the period on or after the Business Combination, the Company, including the consolidation of the Karnes County Business, the Giddings Assets, and the Ironwood Interests is the "Successor". The financial statements and certain footnote presentations separate the Company's presentations into two distinct periods, the period before the consummation of the Business Combination, which includes the period from January 1, 2018 to July 30, 2018 (the "2018 Predecessor Period") and the three and nine months ended September 30, 2017 ("2017 Predecessor Period") and the period on and after the consummation of the Business Combination, which is from July 31, 2018 to September 30, 2018 (the "Successor Period"). The Business Combination was accounted for using the acquisition method of accounting and the Successor financial statements reflect a new basis of accounting that is based on the fair value of net assets acquired and liabilities assumed. As a result of the inclusion of the Giddings Assets, the new basis of accounting, and certain other items that affect comparability, the Company’s financial information prior to the Business Combination is not comparable to its financial information subsequent to the Business Combination. The accompanying unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and in accordance with the rules and regulations of the SEC. Accordingly, certain information and disclosures normally included in annual financial statements prepared in accordance with US GAAP have been condensed or omitted. In the opinion of management, all adjustments, consisting of only normal recurring adjustments, considered necessary for a fair presentation have been included. Interim results are not necessarily indicative of results for the full year or any future periods. The unaudited interim consolidated financial statements, including the Predecessor financial statements, should be read in conjunction with the information included in or incorporated by reference from the Company’s Definitive Proxy Statement on Schedule 14A filed with the SEC on July 2, 2018, including the Karnes County Business annual financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements have been prepared in accordance with US GAAP. Certain reclassifications of prior period financial statements have been made to conform to current reporting practices. The consolidated financial statements include the accounts of the Company and its subsidiaries after elimination of intercompany transactions and balances. The Company’s interests in oil and natural gas exploration and production ventures and partnerships are proportionately consolidated. The Company reflects a noncontrolling interest representing the interest owned by the Karnes County Contributors through their ownership of Magnolia LLC Units in the unaudited consolidated financial statements. The noncontrolling interest is presented as a component of equity. See Note 10—Stockholders' Equity and Parents' Net Investment for further discussion of noncontrolling interest. Variable Interest Entities Magnolia LLC is a variable interest entity (“VIE”). The Company determined that it is the primary beneficiary of Magnolia LLC as the Company is the sole managing member and has the power to direct the activities most significant to Magnolia LLC’s economic performance as well as the obligation to absorb losses and receive benefits that are potentially significant. At September 30, 2018, the Company had an approximate 63.2% economic interest in Magnolia LLC and 100% of Magnolia LLC’s assets and liabilities and results of operations are consolidated in the Company’s unaudited consolidated financial statements contained herein. At September 30, 2018, the Karnes County Contributors had approximately 36.8% economic interest in Magnolia LLC; however, the Karnes County Contributors have disproportionately fewer voting rights, and are shown as noncontrolling interest holders of Magnolia LLC. See Note 10—Stockholders' Equity and Parents' Net Investment for further discussion of noncontrolling interest. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires the Company’s 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, and changes in these estimates are recorded when known. Significant estimates with regard to these financial statements include the fair value determination of acquired assets and liabilities, the assessment of asset retirement obligations, the estimate of proved oil and gas reserves and related present value estimates of future net cash flows, and the estimates of fair value for long-lived assets. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are stated at the historical carrying amount net of write-offs and an allowance for doubtful accounts. The carrying amount of the Company’s accounts receivable approximates fair value because of the short-term nature of the instruments. The Company routinely assesses the collectability of all material trade and other receivables. The Company’s receivables consist mainly of receivables from oil and natural gas purchasers and from joint interest owners on properties the Company operates. The Company accrues a reserve on a receivable when, based on the judgment of management, it is probable that a receivable will not be collected and the amount of any reserve may be reasonably estimated. The Company had no allowance for doubtful accounts as of September 30, 2018 (Successor), or December 31, 2017 (Predecessor). Oil and Natural Gas Properties The Company follows the successful efforts method of accounting for its oil and gas properties. Under this method of accounting, exploration costs such as exploratory geological and geophysical costs, delay rentals, and exploration overhead are expensed as incurred. All costs related to production, general corporate overhead, and similar activities are expensed as incurred. If an exploratory well provides evidence to justify potential development of reserves, drilling costs associated with the well are initially capitalized, or suspended, pending a determination as to whether a commercially sufficient quantity of proved reserves can be attributed to the area as a result of drilling. At the end of each quarter, management reviews the status of all suspended exploratory well costs in light of ongoing exploration activities; in particular, whether the Company is making sufficient progress in its ongoing exploration and appraisal efforts. If management determines that future appraisal drilling or development activities are unlikely to occur, associated suspended exploratory well costs are expensed. Unproved properties are assessed for impairment at least annually and are transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Unproved properties are assessed for impairment based on the Company’s current exploration plans. Costs of expired or abandoned leases are charged to exploration expense, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties, as well as impairment of unsuccessful leases, are included in exploration costs in the consolidated statements of operations. Costs to develop proved reserves, including the costs of all development wells and related equipment used in the production of crude oil and natural gas, are capitalized. Depreciation of the cost of proved oil and gas properties is calculated using the unit-of-production method ("UOP"). The UOP calculation multiplies the percentage of estimated proved reserves produced each quarter by the carrying value of those reserves. The reserve base used to calculate depreciation for leasehold acquisition costs and the cost to acquire proved properties is the sum of proved developed reserves and proved undeveloped reserves. The reserve base used to calculate the depreciation for capitalized costs for exploratory and development wells is the sum of proved developed reserves only. Estimated future dismantlement, restoration and abandonment costs, net of salvage values, are included in the depreciable cost. Oil and gas properties are grouped for depreciation in accordance with the Accounting Standards Codification ("ASC") ASC 932 "Extractive Activities—Oil and Gas” ("ASC 932"). The basis for grouping is a reasonable aggregation of properties with a common geological structural feature or stratigraphic condition, such as a reservoir or field. When circumstances indicate that proved oil and gas properties may be impaired, the Company compares unamortized capitalized costs to the expected undiscounted pre-tax future cash flows for the associated assets grouped at the lowest level for which identifiable cash flows are independent of cash flows of other assets. If the expected undiscounted pre-tax future cash flows, based on the Company’s estimate of future crude oil and natural gas prices, operating costs, anticipated production from proved reserves and other relevant data, are lower than the unamortized capitalized cost, the capitalized cost is reduced to fair value. Fair value is generally estimated using the income approach described in the ASC 820, "Fair Value Measurements" ("ASC 820"). If applicable, the Company utilizes prices and other relevant information generated by market transactions involving assets and liabilities that are identical or comparable to the item being measured as the basis for determining fair value. The expected future cash flows used for impairment reviews and related fair value calculations are typically based on judgmental assessments of future production volumes, commodity prices, operating costs, and capital investment plans, considering all available information at the date of review. These assumptions are applied to develop future cash flow projections that are then discounted to estimated fair value, using a discount rate believed to be consistent with those applied by market participants. Asset Retirement Costs and Obligations Asset retirement obligations represent the present value of the estimated cash flows expected to be incurred to plug, abandon and remediate producing properties, excluding salvage values, at the end of their productive lives in accordance with applicable laws. The significant unobservable inputs to this fair value measurement include estimates of plugging, abandonment and remediation costs, well life, inflation and credit-adjusted risk-free rate. The inputs are calculated based on historical data as well as current estimates. When the liability is initially recorded, the carrying amount of the related long-lived asset is increased. Over time, accretion of the liability is recognized each period, and the capitalized cost is amortized over the useful life of the related asset and is included in "Depreciation, depletion and amortization" in the Company’s consolidated statements of operations. To estimate the fair value of an asset retirement obligation, the Company employs a present value technique, which reflects certain assumptions, including its credit‑adjusted risk‑free interest rate, inflation rate, the estimated settlement date of the liability and the estimated current cost to settle the liability. Changes in timing or to the original estimate of cash flows will result in change to the carrying amount of the liability and related long lived asset. Intangible Asset (Successor) Concurrent with the closing of the Business Combination, the Company and EnerVest entered into a Non-Compete (the "Non-Compete") pursuant to which EnerVest and certain of its affiliates are restricted from competing with the Company in certain counties comprising the Eagle Ford Shale. The Company recorded an estimated cost of $44.4 million for the Non-Compete as an intangible asset on the consolidated balance sheet of the Successor. This intangible asset has a definite life and is subject to amortization utilizing straight line method over its economic life, currently estimated to be two and a half to four years. Magnolia assesses intangible assets for impairment together with related underlying long-lived assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment is recognized in the consolidated statements of operations if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value. For the period ended September 30, 2018, no impairment was recorded. For more discussion on the Non-Compete, refer to Note 6 - Intangible Asset. Fair Value Measurements ASC 820 establishes a fair value hierarchy that prioritizes and ranks the level of observability of inputs used to measure investments at fair value. The observability of inputs is impacted by a number of factors, including the type of investment, characteristics specific to the investment, market conditions and other factors. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level I measurements) and the lowest priority to unobservable inputs (Level III measurements). Investments with readily available quoted prices or for which fair value can be measured from quoted prices in active markets will typically have a higher degree of input observability and a lesser degree of judgment applied in determining fair value. The three levels of the fair value hierarchy under ASC 820 are as follows: Level I—Quoted prices (unadjusted) in active markets for identical investments at the measurement date are used. Level II—Pricing inputs are other than quoted prices included within Level I that are observable for the investment, either directly or indirectly. Level II pricing inputs include quoted prices for similar investments in active markets, quoted prices for identical or similar investments in markets that are not active, inputs other than quoted prices that are observable for the investment, and inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level III—Pricing inputs are unobservable and include situations where there is little, if any, market activity for the investment. The inputs used in determination of fair value require significant judgment and estimation. In some cases, the inputs used to measure fair value might fall within different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the investment is categorized in its entirety is determined based on the lowest level input that is significant to the investment. Assessing the significance of a particular input to the valuation of an investment in its entirety requires judgment and considers factors specific to the investment. The categorization of an investment within the hierarchy is based upon the pricing transparency of the investment and does not necessarily correspond to the perceived risk of that investment. Equity Method Investment As part of the Business Combination, the Company acquired the Ironwood Interests . The Company accounts for its investment in Ironwood using the equity method of accounting. Accordingly, the Company recognizes its proportionate share of Ironwood’s net income in the consolidated statements of operations as “Income from equity method investee”. Any distributions by Ironwood would decrease the Company’s investment in Ironwood. The Company evaluates its investment in Ironwood for potential impairment whenever events or changes in circumstances indicate that there may be a loss in the value of Ironwood that was other than temporary. Income Taxes (Successor) Under ASC 740, “Income Taxes,” deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to net operating losses, tax credits, and temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period of the enactment date. Valuation allowances are established when it is more likely than not that some or all of the deferred tax assets will not be realized. The Company reports a liability or a reduction of deferred tax assets for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. When applicable, the Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. Purchase Price Allocation Accounting for the acquisition of a business requires the allocation of the purchase price to the various assets and liabilities of the acquired business and recording deferred taxes for any differences between the allocated values and tax basis of assets and liabilities. Any excess of the purchase price over the amounts assigned to assets and liabilities is recorded as goodwill. The purchase price allocation is accomplished by recording each asset and liability at its estimated fair value. Estimated deferred taxes are based on available information concerning the tax basis of the acquired company’s assets and liabilities and tax-related carryforwards at the merger date, although such estimates may change in the future as additional information becomes known. The amount of goodwill recorded in any particular Business Combination can vary significantly depending upon the values attributed to assets acquired and liabilities assumed relative to the total acquisition cost. When estimating the fair values of assets acquired and liabilities assumed, the Company must apply various assumptions. The most significant assumptions relate to the estimated fair values assigned to proved and unproved crude oil and natural gas properties. To estimate the fair values of these properties, the Company prepares estimates of crude oil and natural gas reserves. Estimated fair values assigned to assets acquired can have a significant effect on results of operations in the future. Commitments and Contingencies Accruals for loss contingencies arising from claims, assessments, litigation, environmental and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted as additional information becomes available or circumstances change. Refer to Note 13 - Commitments and Contingencies for additional information. Revenue Recognition Oil and gas revenues are recognized when production is sold to a purchaser at a fixed or determinable price, when delivery has occurred and title has transferred, and if collectability of the revenue is probable. Cash received relating to future revenues is deferred and recognized when all revenue recognition criteria are met. The Company follows the sales method of accounting for crude oil and natural gas production imbalances and would recognize a liability if Magnolia's existing proved reserves were not adequate to cover an imbalance. Imbalances have not been significant in the periods presented. Net Income Per Share of Common Stock Basic earnings per common share is calculated by dividing net income attributable to Class A Common Stock by the weighted average number of shares of Class A Common Stock outstanding each period. Diluted earnings per share adds to those shares the incremental shares that would have been outstanding assuming exchanges of the Company's outstanding Class B Common Stock and warrants for Class A Common Stock. An anti-dilutive impact is an increase in earnings per share or a reduction in net loss per share resulting from the conversion, exercise, or contingent issuance of certain securities. The Company uses the "if-converted" method to determine the potential dilutive effect of conversions of its outstanding Class B Common Stock and the treasury stock method to determine the potential dilutive effect of its outstanding warrants exercisable for shares of Class A Common Stock. Refer to Note 11 - Earnings Per Share for additional information and the calculation of net earnings per share. Recent Accounting Pronouncements (Successor) In February 2016, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2016–02, Leases (Topic 842), which will require lessees to recognize a right of use asset and a lease liability on their balance sheet for all leases, including operating leases, with a term of greater than 12 months. Currently the guidance would be applied using a modified retrospective transition method, which requires applying the new guidance to leases that exist or are entered into after the beginning of the earliest period in the financial statements. However, in July 2018, the FASB issued ASU 2018-11, which adds a transition option permitting entities to apply the provisions of the new standard at its adoption date instead of the earliest comparative period presented in the consolidated financial statements. Under this transition option, comparative reporting would not be required, and the provisions of the standard would be applied prospectively to leases in effect at the date of adoption. The standard will be effective for interim and annual periods beginning after December 15, 2018 for public companies and annual periods beginning after December 15, 2019 for all other entities, with earlier adoption permitted. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on January 1, 2019, using the optional transition method provided by ASU 2018-11. The Company is the lessee under various agreements for real estate, vehicles, and field equipment that are currently accounted for as operating leases. The Company has preliminarily determined its portfolio of leased assets and is reviewing all related contracts to determine the impact the adoption will have on its consolidated financial statements. While the Company has yet to finalize the estimated impact this standard will have on the consolidated financial statements, the adoption is anticipated to result in an increase in both assets and liabilities related to the Company's leases. In May 2014, the FASB issued ASU No. 2014–09, Revenue from Contracts with Customers. This ASU, as amended, superseded virtually all of the revenue recognition guidance in generally accepted accounting principles in the United States. The core principle of the five–step model is that an entity will recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on December 31, 2018 , using a modified retrospective approach. Upon initial evaluation of contracts in each of the Company’s revenue streams, the Company does not expect the adoption of this ASU to have a material impact on its consolidated financial statements. The Company continues to evaluate contracts against the requirements of the standard and is evaluating the disclosure requirements and assessing changes to the relevant business processes and the control activities within them as a result of the provisions of this ASU. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows: Classification of Certain Cash". Receipts and Cash Payments (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statements of cash flows. ASU 2016-15 is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017 for public companies and for fiscal years beginning after December 15, 2018 for all other entities. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on December 31, 2018. The adoption of this guidance will not impact the Company's financial position or results of operations but could result in presentation changes on Magnolia's consolidated statements of cash flows. In January 2017, the FASB issued ASU 2017-01 "Business Combinations (Topic 805): Clarifying the Definition of a Business" ("ASU 2017-01"), which clarifies the definition of a business to provide guidance in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 provides a screen to determine when a set of assets is not a business, requiring that when substantially all fair value of gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar identifiable assets, the set of assets is not a business. A framework is provided to assist in evaluating whether both an input and a substantive process are present for the set to be a business. ASU 2017-01 is effective for interim and annual periods after December 15, 2017 for public companies and annual periods beginning after December 15, 2018 for all other entities. No disclosures are required at transition. The Company early adopted ASU 2017-01 upon the closing of the Business Combination. There was no material impact to the Company's financial statements as a result of this adoption, however the new standard may result in more transactions being accounted for as acquisitions (and dispositions) of assets rather than businesses in the future.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions	Acquisitions EnerVest Business Combination As discussed in Note 1 - Description of Business and Basis of Presentation , on July 31, 2018, the Company consummated the Business Combination contemplated by the Business Combination Agreements. The Business Combination Agreements and the Business Combination were approved by the Company’s stockholders on July 17, 2018. At the closing of the Business Combination, the Karnes County Contributors received 83.9 million shares of the Company's Class B Common Stock and an equivalent number of Magnolia LLC Units, which, together, are exchangeable on a one -for-one basis for shares of the Company's Class A Common Stock; 31.8 million shares of Class A Common Stock; and approximately $911.5 million in cash. The sales price per the Karnes County Contribution Agreement was adjusted for customary purchase price adjustments to reflect the economic activity from the effective date of January 1, 2018 to June 30, 2018. The Company is entitled to an additional cash purchase price adjustment for the revenues after expenses (and other purchase price adjustments) attributable to the Acquired Assets from July 1 through July 31. The Giddings Sellers received approximately $282.7 million in cash, after customary purchase price adjustments. The Ironwood Sellers received $25.0 million in cash in exchange for the Ironwood Interests. The final adjustments to the respective purchase price agreements have not yet been made. The Business Combination has been accounted for using the acquisition method. The acquisition method of accounting is based on ASC 805 "Business Combination" ("ASC 805"), and uses the fair value concepts defined in ASC 820. ASC 805 requires, among other things, that the assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date by the Company. Contingent Consideration Pursuant to the Karnes County Contribution Agreement, for a period of five years following the Closing Date, the Karnes County Contributors will be entitled to receive an aggregate of up to 13.0 million additional shares of Class A Common Stock or Class B Common Stock based on certain EBITDA and free cash flow or stock price thresholds. As of September 30, 2018, the Company had met the defined stock price thresholds for two of the three tranches as defined in the Karnes County Contribution Agreement and issued an aggregate of 2.5 million additional shares of Class A Common Stock and 6.5 million additional shares of Class B Common Stock to the Karnes County Contributors. Additionally, on October 4, 2018, the Company met the stock price threshold for the third and final tranche and subsequently issued 1.1 million additional shares of Class A Common Stock and 2.9 million additional shares of Class B Common Stock to the Karnes County Contributors. Pursuant to the Giddings Purchase Agreement, until December 31, 2021, the Giddings Sellers were entitled to receive an aggregate of up to $47.0 million in cash earnout payments based on certain net revenue thresholds. On September 28, 2018 the Company paid the Giddings Sellers a cash payment of $26.0 million to fully settle the earnout obligation. In conjunction with this payment, Magnolia recognized a loss of $6.7 million included in Other income (expense) in the Consolidated Statement of Operations. The purchase consideration for the Business Combination was as follows: At July 31, Preliminary Purchase Consideration: Cash consideration $ 1,219,217 Stock consideration (1) 1,423,483 Fair value of contingent earnout purchase consideration (2) 169,000 Total purchase price consideration $ 2,811,700 (1) At closing of the Business Combination, the Karnes County Contributors received 83.9 million shares of Class B Common Stock and 31.8 million shares of Class A Common Stock. (2) Pursuant to ASC 805, ASC 480, "Distinguishing Liabilities from Equity" and ASC 815, "Derivatives and Hedging", the Karnes County earnout consideration has been valued at fair value as of the Closing Date and has been classified in stockholders’ equity. The Giddings earnout has been valued at fair value as of the Closing Date and has been classified as a liability. The fair value of the earnouts was determined using the Monte Carlo simulation valuation method based on Level 3 inputs in the fair value hierarchy. The following table summarizes the allocation of the purchase consideration to the assets and liabilities assumed: At July 31, 2018 (in thousands) Estimated fair value of assets acquired Account receivable $ 89,674 Other current assets 2,853 Oil & gas properties (1) 2,800,258 Ironwood equity investment 18,100 Total fair value of assets acquired 2,910,885 Estimated fair value of liabilities assumed Accounts payable and other current liabilities (56,315 ) Asset retirement obligation (34,132 ) Deferred tax liability (8,738 ) Fair value of net assets acquired $ 2,811,700 (1) The fair value measurements of oil and natural gas properties and asset retirement obligations are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair values of oil and natural gas properties and asset retirement obligations were measured using valuation techniques that convert future cash flows to a single discounted amount. Significant inputs to the valuation of oil and natural gas properties included estimates of: (i) recoverable reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices; and (v) a market-based weighted average cost of capital rate. These inputs required significant judgments and estimates by management at the time of the valuation and may be subject to change. The total purchase consideration and the related purchase consideration allocation above are preliminary as the Company has not yet completed all the necessary fair value assessments, including the assessments of property, plant and equipment, intangibles, contingent consideration and the related tax impacts on these items. Any changes within the measurement period in the estimated fair values of the assets acquired and liabilities assumed and the working capital adjustments may change the allocation of the purchase consideration. The fair value and related tax impact assessments are to be completed within twelve months of the Closing Date and could have a material impact on the components of the total purchase consideration and the purchase consideration allocation. Transaction costs incurred by the Company associated with the Business Combination were $22.4 million for the Successor Period. The Company also incurred a total of $23.5 million of debt issuance costs in connection with the consummation of the Business Combination related to the establishment of the RBL Facility (as defined herein) and the issuance of the 2026 Senior Notes. Non-Compete On the Closing Date, the Company and EnerVest entered into the Non-Compete restricting EnerVest and certain of its affiliates from competing with the Company in certain counties comprising the Eagle Ford Shale following the Closing Date. An affiliate of EnerVest will have the right to receive up to 4,000,000 shares of Class A Common Stock issuable in two and half to four years provided EnerVest does not compete. For more discussion on the Non-Compete, refer to Note 6 - Intangible Asset . Unaudited Pro Forma Operating Results The following unaudited pro forma combined financial information has been prepared as if the Business Combination and other related transactions had taken place on January 1, 2017. The information reflects pro forma adjustments based on available information and certain assumptions that the Company believes are reasonable, including depletion of the Company’s fair-valued proved oil and gas properties, and the estimated tax impacts of the pro forma adjustments. Additionally, pro forma net income attributable to Class A Common Stock excludes $34.3 million of transaction related costs, $11.0 million related to a one time purchase of a seismic license continuation, and a $6.7 million loss related to the settlement of the Giddings earnout obligation. The pro forma combined financial information has been included for comparative purposes and is not necessarily indicative of the results that might have actually occurred had the Business Combination taken place on January 1, 2017; furthermore, the financial information is not intended to be a projection of future results. (Unaudited Pro Forma) (in thousands) Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 Total Revenues $ 267,659 $ 110,294 $ 723,768 $ 356,254 Net income attributable to Class A Common Stock 57,891 6,531 151,316 26,257 Income per share - basic 0.39 0.04 1.02 0.21 Income per share - diluted 0.38 0.04 0.98 0.20 Harvest Acquisition On August 31, 2018, the Company completed the acquisition to purchase substantially all of the South Texas assets of Harvest Oil & Gas Corporation for approximately $133.3 million in cash and 4.2 million newly issued shares of the Company’s Class A Common Stock for a total consideration of $191.5 million . The acquisition added an undivided working interest across a portion of Magnolia's existing Karnes County Assets and all of the Company's existing Giddings Assets. The following table summarizes the allocation of the purchase consideration to the assets and liabilities assumed: At August 31, 2018 (in thousands) Estimated fair value of assets acquired Other current assets $ 1,290 Oil & gas properties (1) 200,035 Total fair value of assets acquired 201,325 Estimated fair value of liabilities assumed Asset retirement obligation and other current liabilities (9,812 ) Fair value of net assets acquired $ 191,513 (1) The fair value measurements of oil and natural gas properties and asset retirement obligations are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair values of oil and natural gas properties and asset retirement obligations were measured using valuation techniques that convert future cash flows to a single discounted amount. Significant inputs to the valuation of oil and natural gas properties included estimates of: (i) recoverable reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices; and (v) a market-based weighted average cost of capital rate. These inputs required significant judgments and estimates by management at the time of the valuation and may be subject to change. The total purchase consideration and the related purchase consideration allocation above are preliminary as the Company has not yet completed all the necessary fair value assessments, including the assessments of property, plant and equipment. Any changes within the measurement period in the estimated fair values of the assets acquired and liabilities assumed and the working capital adjustments may change the allocation of the purchase consideration. The fair value assessments are to be completed within twelve months of the closing date and could have a material impact on the components of the total purchase consideration and the purchase consideration allocation. Acquisitions (Predecessor) GulfTex Acquisition On March 1, 2018, the Predecessor acquired certain oil and natural gas properties located in the Eagle Ford Shale from GulfTex Energy III, L.P. and GulfTex Energy IV, L.P. for an adjusted purchase price of approximately $150.1 million , net of customary closing adjustments (the “Subsequent GulfTex Acquisition”). The recognized fair value of identifiable assets and acquired liabilities assumed in connection with the Subsequent GulfTex Acquisition, is as follows: (In thousands) Total consideration $ 150,139 Purchase price allocation: Accounts receivable 10,501 Proved oil and natural gas properties 118,572 Unproved oil and natural gas properties 22,802 Accounts payable and accrued liabilities (1,679 ) Asset retirement obligations (57 ) $ 150,139 BlackBrush Acquisition On January 31, 2017, the Predecessor acquired assets from BlackBrush Karnes Properties, LLC for aggregate consideration of approximately $58.7 million , net of customary closing adjustments (the “Subsequent BlackBrush Acquisition”). The recognized fair value of identifiable assets and acquired liabilities assumed in connection with the Subsequent BlackBrush Acquisition, is as follows: (In thousands) Total consideration $ 58,653 Purchase price allocation: Accounts receivable 2,193 Proved oil and natural gas properties 57,263 Unproved oil and natural gas properties 1,552 Accounts payable and accrued liabilities (2,244 ) Asset retirement obligations (111 ) $ 58,653 The Predecessor accounted for these acquisitions as Business Combinations. The assets acquired and the liabilities assumed have been measured at fair value based on various estimates. These estimates are based on key assumptions related to the Business Combination, including reviews of publicly disclosed information for other acquisitions in the industry, historical experience of the companies, data that was available through the public domain and due diligence reviews of the acquired business. Any acquisition related transaction costs are not included as components of consideration transferred but are accounted for as expenses in the period in which the costs are incurred. The results of operations for these acquisitions are included in the Predecessor combined financial statements from the date of closing of each acquisition.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities (Predecessor)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities (Predecessor) The Company's activities expose it to risks associated with changes in the market price of oil, natural gas and natural gas liquids. As such, future earnings are subject to fluctuation due to changes in the market price of oil, natural gas and natural gas liquids. The Company does not engage in any hedging activities and does not expect to engage in any hedging activities with respect to the market risk to which the Company is exposed. The Karnes County Contributors, on behalf of the Predecessor, used derivatives to reduce its risk of volatility in the prices of oil, natural gas and natural gas liquids and its policies did not permit the use of derivatives for speculative purposes. The Predecessor elected not to designate any of its derivatives as hedging instruments. Accordingly, changes in the fair value of the Predecessor's derivatives are recorded immediately to earnings as “Gain (loss) on derivatives, net” in the consolidated statements of operations. During the period from January 1, 2018 through July 30, 2018, the Predecessor terminated substantially all of its derivative contracts which, together with regular monthly settlements, resulted in total cash settlement payments of approximately $27.6 million . The following table sets forth the fair values and classification of the outstanding derivatives entered into by the Karnes County Contributors, on behalf of the Predecessor, as of December 31, 2017 : (In thousands) Gross Amounts of Recognized Assets Gross Amounts of Offset in the Balance Sheet Net Amounts Of Assets Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative asset $ 180 $ (180 ) $ — Long-term derivative asset 48 (48 ) — Total $ 228 $ (228 ) $ — Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts Of Liabilities Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative liability $ 6,944 $ (180 ) $ 6,764 Long-term derivative liability 3,100 (48 ) 3,052 Total $ 10,044 $ (228 ) $ 9,816 The Predecessor entered into master netting arrangements with its counterparties. The amounts above are presented on a net basis in the Predecessor's unaudited consolidated balance sheet when such amounts are with the same counterparty. In addition, the Predecessor has recorded accounts payable and receivable balances related to settled derivatives that are subject to the master netting agreements. These amounts are not included in the above table; however, under the master netting agreements, the Predecessor has the right to offset these positions against forward exposure related to outstanding derivatives.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Certain of the Company’s assets and liabilities are carried at fair value and measured either on a recurring or non-recurring basis. The Company's fair value measurements are based either on actual market data or assumptions that other market participants would use in pricing an asset or liability in an orderly transaction, using the valuation hierarchy prescribed by GAAP. See Note 2 - Summary of Significant Accounting Policies for more information regarding the valuation hierarchy. Fair Values - Recurring (Predecessor) The Predecessor derivatives consist of over-the-counter (“OTC”) contracts which are not traded on a public exchange. As the fair value of these derivatives is based on inputs using market prices obtained from independent brokers or determined using quantitative models that use as their basis readily observable market parameters that are actively quoted and can be validated through external sources, including third party pricing services, brokers and market transactions, the Predecessor categorized these derivatives as Level 2. The Predecessor valued these derivatives using the income approach using inputs such as the forward curve for commodity prices based on quoted market prices and prospective volatility factors related to changes in the forward curves. Estimates of fair value have been determined at discrete points in time based on relevant market data. Furthermore, fair values are adjusted to reflect the credit risk inherent in the transaction, which may include amounts to reflect counterparty credit quality and/or the effect of the Predecessor’s creditworthiness. These assumed credit risk adjustments are based on published credit ratings, public bond yield spreads and credit default swap spreads. The following table presents the fair value hierarchy table for the Predecessor’s assets and liabilities that are required to be measured at fair value on a recurring basis: (In thousands) Level 1 Level 2 Level 3 Total Fair Value As of December 31, 2017 (Predecessor): Assets: Oil, natural gas and natural gas liquids derivatives $ — $ 228 $ — $ 228 Liabilities: Oil, natural gas and natural gas liquids derivatives $ — $ 10,044 $ — $ 10,044 Fair Values - Nonrecurring The fair value measurements of assets acquired and liabilities assumed in a business combination are measured on a nonrecurring basis on the acquisition date using an income valuation technique based on inputs that are not observable in the market and therefore represent Level 3 inputs. Significant inputs to the valuation of acquired oil and gas properties includes estimates of: (i) reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices, including price differentials; (v) future cash flows; and (vi) a market participant-based weighted average cost of capital rate. These inputs require significant judgments and estimates by the Company's management at the time of the valuation. Refer to Note 3 - Acquisitions for additional information. Debt obligations Carrying values and fair values of financial instruments that are not carried at fair value in the accompanying consolidated balance sheets as of September 30, 2018 is as follows: September 30, 2018 (In thousands) Carrying Value Fair Value Long-term debt $ 388,343 $ 399,000 The fair value of the 2026 Senior Notes at September 30, 2018 was based on unadjusted quoted prices in an active market, which are considered a Level 1 input in the fair value hierarchy. The Company has other financial instruments consisting primarily of receivables, payables and other current assets and liabilities that approximate fair value due to the nature of the instrument and their relatively short maturities. Non-financial assets and liabilities initially measured at fair value include assets acquired and liabilities assumed in the Business Combination and asset retirement obligations.

Intangible Asset

Intangible Asset	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Asset	Intangible Asset Non-Compete Agreement On the Closing Date, the Company and EnerVest entered into the Non-Compete, which prohibits EnerVest and certain of its affiliates from competing with the Company in the Eagle Ford Shale (the “Market Area”) following the Closing Date. Under the Non-Compete, an affiliate of EnerVest will have the right to receive up to 4.0 million shares of Class A Common Stock, subject to the achievement of certain stock price thresholds that were met by October 4, 2018. The shares are issuable in two and a half to four years provided EnerVest does not compete in the Market Area. The Company recorded an estimated cost of $44.4 million for the Non-Compete as an intangible asset on the consolidated balance sheet of the Successor. This intangible asset has a definite life and is subject to amortization utilizing the straight line method over its economic life, currently estimated to be two and a half to four years. The Company includes the amortization in depreciation, depletion and amortization expenses on the Company’s consolidated statements of operations. (In thousands) September 30, 2018 (Successor) Non-Compete Intangible Asset $ 44,400 Accumulated amortization (2,417 ) Intangible, net $ 41,983 Weighted average amortization (years) 3.25

Asset Retirement Obligation

Asset Retirement Obligation	9 Months Ended
	Sep. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	Asset Retirement Obligation A summary of the changes in asset retirement obligations is included in the table below: (In thousands) 2018 Balance, as of January 1 (Predecessor) $ 3,929 Liabilities incurred and assumed through acquisitions 553 Liabilities settled (85 ) Accretion expense 104 Balance, as of July 30 (Predecessor) $ 4,501 Balance, as of July 31 (Successor) $ — Liabilities incurred and assumed through acquisitions 43,930 Liabilities settled — Accretion expense 391 Balance, as of September 30 (Successor) 44,321 Less: Current portion (884 ) Long-term portion $ 43,437

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company estimates its annual effective tax rate in recording its quarterly provision for income taxes in the various jurisdictions in which Magnolia operates. The tax effects of statutory rate changes, significant unusual or infrequent items, and certain changes in the assessment of the realizability of deferred tax assets are excluded from the determination of the Company's annual effective tax rate as such items are recognized as discrete items in the quarter in which they occur. Income tax expense recorded in the Successor Period is based on applying an estimated annual effective income tax rate to the net income from July 31, 2018 through September 30, 2018. There were no significant unusual or infrequently occurring items that are required to be recorded as discrete items in the Successor Period. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the Successor’s expected operating income for the year, projections of the proportion of income earned and taxed in various jurisdictions, the effect of noncontrolling interest, permanent and temporary differences and the likelihood of recovering deferred tax assets in the current year. The accounting estimates used to compute the income tax benefit may change as new events occur, more experience is obtained, additional information becomes known or as the tax environment changes. For the Successor Period, the Company incurred United States federal income tax expense of approximately $3.5 million . The Company's annual effective tax rate as of September 30, 2018 was 12.2% . The primary differences between the annual effective tax rate and the statutory rate of 21% were income attributable to noncontrolling interest, state taxes, and non-deductible expenses. The Company's income tax provision (benefit) consisted of the following components: (In thousands) Successor Predecessor July 31, 2018 through September 30, 2018 July 1, 2018 through July 30, 2018 January 1, 2018 through July 30, 2018 Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Current: Federal $ — $ — $ — $ — $ — State 45 631 1,461 81 848 45 631 1,461 81 848 Deferred: Federal 3,493 — — — — State — 135 324 549 1,119 3,493 135 324 549 1,119 Total provision $ 3,538 $ 766 $ 1,785 $ 630 $ 1,967 The Company is subject to U.S. federal income tax as well as the margin tax in the state of Texas. No amounts have been accrued for income tax uncertainties or interest and penalties as of September 30, 2018. The Company is currently not aware of any issues under review that could result in significant payments, accruals or material deviation from its position. The Company is open to possible income tax examinations by its major taxing authorities since Inception.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long Term Debt (Successor) The Company's debt is comprised of the following: (In thousands) Successor September 30, 2018 Revolving credit facility $ — 6.0% Senior Notes due 2026 400,000 Total long-term debt 400,000 Less: unamortized deferred financing cost (11,657 ) Total debt, net $ 388,343 Credit Facility In connection with the consummation of the Business Combination, Magnolia Operating entered into a senior secured reserve-based revolving credit facility (the “RBL Facility”) among Magnolia Operating, as borrower, Magnolia Intermediate, as holdings, the banks, financial institutions and other lending institutions from time to time party thereto, as lenders, the other parties from time to time party thereto and Citibank, N.A., as administrative agent, collateral agent, issuing bank and swingline lender, providing for maximum commitments in an aggregate principal amount of $1.0 billion with a letter of credit facility with a $100.0 million sublimit. The borrowing base as of September 30, 2018 was $550 million . The RBL Facility is guaranteed by certain parent companies and subsidiaries of Magnolia LLC and is collateralized by certain of our oil and natural gas properties and has a borrowing base subject to semi-annual redetermination. Borrowings under the RBL Facility bear interest, at Magnolia Operating’s option, at a rate per annum equal to either the adjusted LIBOR rate or the alternative base rate plus the applicable margin. Additionally, Magnolia Operating is required to pay a commitment fee quarterly in arrears in respect of unused commitments under the RBL Facility. The applicable margin and the commitment fee rate are calculated based upon the utilization levels of the RBL Facility as a percentage of the borrowing base then in effect. The RBL Facility contains certain affirmative and negative covenants customary for financings of this type, including compliance with a leverage ratio of 4.00 to 1.00 and, if the leverage ratio is in excess of 3.00 to 1.00, current ratio of 1.00 to 1.00. As of September 30, 2018 , the Company was in compliance with all covenants (including the financial covenants) under the RBL Facility. Deferred financing costs incurred in connection with securing the RBL Facility were $ 11.7 million which will be amortized on a straight-line basis over a period of five years and included in "Interest expense" in the Company's consolidated statements of operations. During the Successor Period ended September 30, 2018 , the Company recognized interest expense of $0.8 million , related to the RBL Facility. The unamortized portion of the deferred financing costs are included in "Deferred financing costs, net" on the accompanying unaudited consolidated balance sheet as of September 30, 2018. The Company did not have any outstanding borrowings under its RBL Facility as of September 30, 2018 . 2026 Senior Notes On the Closing Date, the Issuers closed the previously announced private offering of $ 400.0 million aggregate principal amount of 2026 Senior Notes. The 2026 Senior Notes were issued under the Indenture, dated as of the Closing Date (the “Indenture”), by and among the Issuers and Deutsche Bank Trust Company Americas, as trustee (the “Trustee”). The 2026 Senior Notes are guaranteed on a senior unsecured basis by the Company, Magnolia Operating and Magnolia Intermediate and may be guaranteed by certain future subsidiaries of the Company. The 2026 Senior Notes will mature on August 1, 2026. The Notes bear interest at the rate of 6.0% per annum, payable semi-annually in arrears on each February 1st and August 1st, commencing February 1, 2019. At any time prior to August 1, 2021, the Issuers may, on any one or more occasions, redeem all or a part of the 2026 Senior Notes at a redemption price equal to 100% of the principal amount of the Notes redeemed, plus a “make whole” premium on accrued and unpaid interest, if any, to, but excluding, the date of redemption. Deferred financing costs incurred in connection with securing the 2026 Senior Notes were $11.8 million which were capitalized and will be amortized using the effective interest method over the term of the 2026 Senior Notes and included in "Interest expense" in the Company's consolidated statement of operations. The unamortized portion of the deferred financing costs is included as a reduction to the carrying value of the 2026 Senior Notes which have been recorded as Long-term debt, net on the consolidated balance sheet as of September 30, 2018. During the Successor Period, the Company recognized interest expense of $4.2 million , related to the 2026 Senior Notes. Affiliate Guarantors All of the Company's wholly owned subsidiaries are guarantors under the terms of its Senior Notes and RBL Facility. The parent guarantees may be released upon the request of Magnolia Operating. Magnolia's consolidated financial statements reflect the financial position of these subsidiary guarantors. As the parent company, Magnolia has no independent operations, assets, or liabilities. The guarantees are full and unconditional (except for customary release provisions) and joint and several. There are restrictions on dividends, distributions, loans or other transfers of funds from the subsidiary guarantors to the Company.

Stockholders' Equity and Parent

Stockholders' Equity and Parents' Net Investment	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity and Parents' Net Investment	Stockholders' Equity and Parents' Net Investment Stockholders' Equity (Successor) Class A Common Stock In connection with the closing of the Business Combination, the Company increased the number of authorized shares of Class A Common Stock to 1.3 billion . At September 30, 2018 , there were 155.2 million shares of Class A Common Stock issued and outstanding. The holders of Class A Common Stock and Class B Common Stock vote together as a single class on all matters and are entitled one vote for each share held. There is no cumulative voting with respect to the election of directors, which results in the holders of more than 50% of the shares being able to elect all of the directors. In the event of a liquidation, dissolution or winding up of the Company, the common stockholders are entitled to share ratably in all assets remaining available for distribution to them after payment of liabilities and after provision is made for each class of stock, if any, having preference over the common stock. The Company's common stockholders have no preemptive or other subscription rights. There are no sinking fund provisions applicable to the common stock. Class B Common Stock In connection with the closing of the Business Combination, the Company authorized 225.0 million shares of Class B Common Stock. At September 30, 2018, there were 90.5 million shares of Class B Common Stock issued and outstanding. Holders of Class B Common Stock will vote together as a single class with holders of Class A Common Stock on all matters properly submitted to a vote of the stockholders. The holders of Class B Common Stock generally have the right to exchange all or a portion of their Class B Common Stock, together with an equal number of Magnolia LLC Units, for the same number shares of Class A Common Stock or, at Magnolia LLC’s option, an equivalent amount of cash. Upon the future redemption or exchange of Magnolia LLC Units held by any holder of Class B Common Stock, a corresponding number of shares of Class B Common Stock held by such holder of Class B Common Stock will be canceled. In the event of a liquidation, dissolution or winding up of the Company, the common stockholders are entitled to share ratably in all assets remaining available for distribution to them after payment of liabilities and after provision is made for each class of stock, if any, having preference over the common stock. The Company's common stockholders have no preemptive or other subscription rights. There are no sinking fund provisions applicable to the common stock. Warrants As of September 30, 2018 , the Company had 31.7 million warrants outstanding, consisting of 21.7 million public warrants originally sold as part of the units sold in the initial public offering (the "IPO") of TPG Pace Energy Holdings Corp., a Delaware corporation ("TPGE") that later became Magnolia after the completion of the Business Combination, and 10.0 million warrants (the "Private Placement Warrants") sold in a private placement concurrently with the IPO to the TPG Pace Energy Sponsor LLC, a Delaware limited liability company (the "Sponsor"). Each whole warrant entitles the holder to purchase one whole share of Class A Common Stock for $11.50 per share. The warrants became exercisable on August 30, 2018 and will expire on July 31, 2023 or earlier upon redemption or liquidation. The Company may redeem the outstanding warrants at a price of $0.01 per existing warrant, if the last sale price of Magnolia's Class A Common Stock equals or exceeds $18.00 per share for any 20 trading days within a 30 trading day period ending on the third business day before Magnolia sends the notice of redemption to the warrant holders. The Private Placement Warrants, however, are non-redeemable so long as they are held by the Sponsor or its permitted transferees. Noncontrolling Interest The noncontrolling interest relates to Magnolia LLC Units that were issued to the Karnes County Contributors in connection with the Business Combination. The noncontrolling interest percentage is affected by various equity transactions such as issuances of Class A Common Stock, exercise of warrants and conversion of Class B Common Stock to Class A Common Stock. As of September 30, 2018 , the Company owned approximately 63.2% of the interest in Magnolia LLC and the noncontrolling interest was 36.8% . Net income attributable to Class A Common Stock for the Successor Period includes all of the one-time transaction costs of $22.4 million incurred in connection with Business Combination as well as all of the federal income tax expense of $3.5 million .

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share A reconciliation of the numerators and denominators of the basic and diluted per share computations follows. No such computation is necessary for the Predecessor periods as the Predecessor was not previously accounted for as a standalone legal entity and did not have publicly traded shares. Successor (In thousands) July 31, 2018 through September 30, 2018 Basic: Net Income attributable to Class A Common Stock $ 6,708 Weighted average number of common shares outstanding during the period 151,992 Net income per common share - basic $ 0.04 Diluted: Net Income attributable to Class A Common Stock $ 6,708 Basic weighted average number of common shares outstanding during the period 151,992 Add: Dilutive effect of warrants 5,080 Diluted weighted average number of common shares outstanding during the period 157,072 Net income per common share - diluted $ 0.04 The calculation for weighted average shares reflects shares outstanding over the reporting period based on the actual number of days the shares were outstanding. For the period presented, the Company excluded 87.6 million shares of Class A Common Stock issuable upon conversion of the Company’s Class B Common Stock (and the corresponding Magnolia LLC Units) as the effect was anti-dilutive.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions As of September 30, 2018, EnerVest Energy Institutional Fund XIV-A, L.P., a Delaware limited partnership, and EnerVest Energy Institutional Fund XIV-C, L.P., a Delaware limited partnership, both entities which are part of the Karnes County Contributors group as defined in Note 1 - Description of Business and Basis of Presentation , each held more than 10% of the Company's common stock and qualified as principal owners of the Company, as defined in ASC 850, "Related Party Disclosures." In addition, the Sponsor had a beneficial ownership of approximately 10% and also qualified as a principal owner of the Company. Amended and Restated Limited Liability Company Agreement of Magnolia LLC On the Closing Date, the Company, Magnolia LLC and certain of the Karnes County Contributors entered into Magnolia LLC’s amended and restated limited liability company agreement , which sets forth, among other things, the rights and obligations of the holders of units in Magnolia LLC. Under the Magnolia LLC Agreement, the Company became the sole managing member of Magnolia LLC. Registration Rights Agreement At the closing of the Business Combination, the Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the Karnes County Contributors, the Sponsor, and the Company’s four independent directors prior to the Business Combination (collectively, the “Holders”), pursuant to which the Company will be obligated, subject to the terms thereof and in the manner contemplated thereby, to register for resale under the Securities Act all or any portion of the shares of Class A Common Stock that the Holders hold as of July 31, 2018 and that they may acquire thereafter, including upon conversion, exchange or redemption of any other security therefor. Under the New Registration Rights Agreement, Holders also have “piggyback” registration rights exercisable at any time that allow them to include the shares of Class A Common Stock that they own in certain registrations initiated by the Company. On August 10, 2018, the Company filed a Registration Statement on Form S-3 (subsequently amended by Amendment No. 1 on August 28, 2018, the “Registration Statement”) to register the Private Placement Warrants and shares of the Company’s Class A Common Stock, including all of shares of Class A Common Stock held by Holders as of July 31, 2018. The Registration Statement was declared effective by the Securities and Exchange Commission on August 30, 2018. Stockholder Agreement On the Closing Date, the Company, Sponsor, and the Karnes County Contributors entered into the Stockholder Agreement (the “Stockholder Agreement”). Under the Stockholder Agreement, the Karnes County Contributors were entitled to nominate two directors, one of whom shall be independent under the listing rules of the New York Stock Exchange, the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the Sarbanes-Oxley Act of 2002, for appointment to the board of directors of the Company (the “Board”) so long as they collectively own at least 15% of the outstanding shares of Class A Common Stock and Class B Common Stock, (on a fully diluted basis, including equity securities exercisable into common stock, and on a combined basis), and one director so long as they owned at least 2% of the outstanding shares of Class A Common Stock and Class B Common Stock (on a fully diluted basis, including equity securities exercisable into common stock, and on a combined basis). Sponsor is entitled to nominate two directors for appointment to the Board so long as it owns at least 60% of the voting common stock that it owns at the Closing Date (including any shares of common stock issuable upon the exercise of any Private Placement Warrants held by Sponsor), and one director so long as it owns at least 25% of the voting common stock that it owns at the Closing Date (including any shares of common stock issuable upon the exercise of any Private Placement Warrants held by Sponsor). The Karnes County Contributors and Sponsor are each entitled to appoint one director to each committee of the Board (subject to applicable law and stock exchange rules). Contingent Consideration Pursuant to the Karnes County Contribution Agreement, for a period of five years following the Closing Date, the Company agreed to issue to the Karnes County Contributors up to 13.0 million additional shares of the Company's stock upon satisfaction of certain EBITDA and free cash flow or stock price thresholds in three tranches. As of September 30, 2018, the Company had met stock price thresholds required for two of the three tranches and thus had issued an aggregate of 2.5 million additional shares of Class A Common Stock and 6.5 million additional shares of Class B Common Stock to the Karnes County Contributors. The effect of this share issuance is included in Magnolia's basic share count as of September 30, 2018. Additionally, on October 4, 2018, Magnolia met the stock price threshold for the third and final tranche and subsequently issued 1.1 million additional shares of Class A Common Stock and 2.9 million additional shares of Class B Common Stock to the Karnes County Contributors. The effect of this share issuance is not reflected in these financial statements. Sponsor Loan At the closing of the Business Combination, the Company repaid in full $1.0 million unsecured promissory note to the Sponsor. Related Party (Predecessor) EnerVest, as managing general partner of the Karnes County Contributors, provided management, accounting and advisory services to the Karnes County Contributors in exchange for a quarterly management fee based on the Karnes County Contributors' investor commitments. The management fees incurred have been allocated to the Predecessor using a ratio of asset acquisitions value to total asset acquisitions completed by the Karnes County Contributors. The management fees allocated to the Predecessor and included in "General and administrative expenses" in the combined statements of operations were $1.5 million and $3.9 million for the period of July 1, 2018 through July 30, 2018 and three months ended September 30, 2017, respectively, and $9.8 million and $11.3 million for the period of January 1, 2018 through July 30, 2018 and nine months ended September 30, 2017, respectively. The Karnes County Contributors also entered into operating agreements with EnerVest Operating, LLC (“EVOC”), a wholly-owned subsidiary of EnerVest, to act as contract operator of the Predecessors’ oil and natural gas wells. The Predecessor reimbursed EVOC for direct expenses incurred. A majority of such expenses are charged on an actual basis (i.e., no mark-up or subsidy is charged or received by EVOC). These costs are included in lease operating expenses in the consolidated statements of operations in the Predecessor period. Additionally, in its role as contract operator, EVOC also collected proceeds from oil, natural gas and natural gas liquids sales and distributed them to the Predecessor and other working interest owners. Accounts receivable from EVOC and other related parties was $13.7 million as of December 31, 2017.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Matters The Company is involved in disputes or legal actions in the ordinary course of business. For example, certain of the Karnes County Contributors have been named as defendants in a lawsuit where the plaintiffs claim to be entitled to a minority working interest in certain Karnes County Business properties. The litigation is in the discovery stage. The exposure related to this litigation is currently not reasonably estimable. The Karnes County Contributors retained all such liability in connection with the Business Combination. In the 2018 Successor Period, the Company does not believe the outcome of any such disputes or legal actions will have a material effect on its unaudited financial statements. No amounts were accrued with respect to outstanding litigation during the 2017 or 2018 Predecessor Periods or during the Successor Period. Environmental Matters The Company, as an owner or lessee and operator of oil and gas properties, is subject to various federal, state, local laws and regulations relating to discharge of materials into, and protection of, the environment. These laws and regulations may, among other things, impose liability on the lessee under an oil and gas lease for the cost of pollution clean-up resulting from operations and subject the lessee to liability for pollution damages. In some instances, the Company may be directed to suspend or cease operations in the affected area. The Company maintains insurance coverage, which it believes is customary in the industry, although the Company is not fully insured against all environmental risks. Commitments At September 30, 2018 , contractual obligations for long-term operating leases and purchase obligations are as follows: Net Minimum Commitments (in thousands) Remainder of 2018 2019 2020 2021 2022 Thereafter Total Purchase obligations (1) $ 7,977 $ 14,641 $ 2,346 $ 131 $ 131 $ 241 $ 25,467 Operating lease obligations (2) 109 436 274 44 — — 863 Service fee commitment (3) 5,891 23,564 13,745 — — — 43,200 Total Net Minimum Commitments $ 13,977 $ 38,641 $ 16,365 $ 175 $ 131 $ 241 $ 69,530 (1) Amounts represent any agreements to purchase goods or services that are enforceable and legally binding and that specify all significant terms. These include minimum commitments associated with firm transportation contracts and frac sand commitments. (2) Amounts include long-term lease payments for compressors, vehicles and office space. (3) On the Closing Date, the Company and EVOC entered into a Services Agreement (the "Services Agreement"), pursuant to which EVOC, under the direction of the Company’s management, will provide the Company's services identical to the services historically provided by EVOC in operating the Acquired Assets, including administrative, back office and day-to-day field level services reasonably necessary to operate the business of the Company and its assets, subject to certain exceptions. As consideration for the services to be provided under the Services Agreement, the Company will pay EVOC a fixed annual services fee of approximately $23.6 million . The annual services fee may be (a) increased or decreased to account for asset acquisitions and dispositions of assets, (b) increased to account for an increase in the rig count attributable to the assets and (c) decreased if the Company must perform any of such services itself because EVOC is unable or fails to do so. The term of the Services Agreement is five years , but the Services Agreement is subject to termination by either party after two years . Risks and Uncertainties The Company’s revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which depend on numerous factors beyond the Company’s control such as overall oil and natural gas production and inventories in relevant markets, economic conditions, the global political environment, regulatory developments and competition from other energy sources. Oil and natural gas prices historically have been volatile, and may be subject to significant fluctuations in the future.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated subsequent events through November 13, 2018 and has determined, other than those disclosed, there are no events that required disclosure or recognition in these unaudited consolidated financial statements. On October 4, 2018, the Company met the stock price threshold for the third and final tranche of the Karnes County earnout consideration and subsequently issued 1.1 million additional shares of Class A Common Stock and 2.9 million additional shares of Class B Common Stock to the Karnes County Contributors. The effect of this share issuance will be included in the Company's year end filing.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation As a result of the Business Combination, the Company is the acquirer for accounting purposes and the Karnes County Business, the Giddings Assets, and the Ironwood Interests are the acquirees. The Karnes County Business, including as applicable, its ownership of the Ironwood Interests, was deemed the "Predecessor" for periods prior to the Business Combination, and does not include the consolidation of the Company and the Giddings Assets. The assets, liabilities, revenues, expenses and cash flows related to the Karnes County Business were not previously separately accounted for as a standalone legal entity and have been carved out of the overall assets, liabilities, revenues, expenses and cash flows from the Karnes County Contributors as appropriate. For the period on or after the Business Combination, the Company, including the consolidation of the Karnes County Business, the Giddings Assets, and the Ironwood Interests is the "Successor". The financial statements and certain footnote presentations separate the Company's presentations into two distinct periods, the period before the consummation of the Business Combination, which includes the period from January 1, 2018 to July 30, 2018 (the "2018 Predecessor Period") and the three and nine months ended September 30, 2017 ("2017 Predecessor Period") and the period on and after the consummation of the Business Combination, which is from July 31, 2018 to September 30, 2018 (the "Successor Period"). The Business Combination was accounted for using the acquisition method of accounting and the Successor financial statements reflect a new basis of accounting that is based on the fair value of net assets acquired and liabilities assumed. As a result of the inclusion of the Giddings Assets, the new basis of accounting, and certain other items that affect comparability, the Company’s financial information prior to the Business Combination is not comparable to its financial information subsequent to the Business Combination. The accompanying unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and in accordance with the rules and regulations of the SEC. Accordingly, certain information and disclosures normally included in annual financial statements prepared in accordance with US GAAP have been condensed or omitted. In the opinion of management, all adjustments, consisting of only normal recurring adjustments, considered necessary for a fair presentation have been included. Interim results are not necessarily indicative of results for the full year or any future periods. The unaudited interim consolidated financial statements, including the Predecessor financial statements, should be read in conjunction with the information included in or incorporated by reference from the Company’s Definitive Proxy Statement on Schedule 14A filed with the SEC on July 2, 2018, including the Karnes County Business annual financial statements.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements have been prepared in accordance with US GAAP. Certain reclassifications of prior period financial statements have been made to conform to current reporting practices. The consolidated financial statements include the accounts of the Company and its subsidiaries after elimination of intercompany transactions and balances. The Company’s interests in oil and natural gas exploration and production ventures and partnerships are proportionately consolidated. The Company reflects a noncontrolling interest representing the interest owned by the Karnes County Contributors through their ownership of Magnolia LLC Units in the unaudited consolidated financial statements. The noncontrolling interest is presented as a component of equity. See Note 10—Stockholders' Equity and Parents' Net Investment for further discussion of noncontrolling interest.
Variable Interest Entities	Variable Interest Entities Magnolia LLC is a variable interest entity (“VIE”). The Company determined that it is the primary beneficiary of Magnolia LLC as the Company is the sole managing member and has the power to direct the activities most significant to Magnolia LLC’s economic performance as well as the obligation to absorb losses and receive benefits that are potentially significant. At September 30, 2018, the Company had an approximate 63.2% economic interest in Magnolia LLC and 100% of Magnolia LLC’s assets and liabilities and results of operations are consolidated in the Company’s unaudited consolidated financial statements contained herein. At September 30, 2018, the Karnes County Contributors had approximately 36.8% economic interest in Magnolia LLC; however, the Karnes County Contributors have disproportionately fewer voting rights, and are shown as noncontrolling interest holders of Magnolia LLC. See Note 10—Stockholders' Equity and Parents' Net Investment for further discussion of noncontrolling interest.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires the Company’s 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, and changes in these estimates are recorded when known. Significant estimates with regard to these financial statements include the fair value determination of acquired assets and liabilities, the assessment of asset retirement obligations, the estimate of proved oil and gas reserves and related present value estimates of future net cash flows, and the estimates of fair value for long-lived assets.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are stated at the historical carrying amount net of write-offs and an allowance for doubtful accounts. The carrying amount of the Company’s accounts receivable approximates fair value because of the short-term nature of the instruments. The Company routinely assesses the collectability of all material trade and other receivables. The Company’s receivables consist mainly of receivables from oil and natural gas purchasers and from joint interest owners on properties the Company operates. The Company accrues a reserve on a receivable when, based on the judgment of management, it is probable that a receivable will not be collected and the amount of any reserve may be reasonably estimated. The Company had no allowance for doubtful accounts as of September 30, 2018 (Successor), or December 31, 2017 (Predecessor).
Oil and Natural Gas Properties	Oil and Natural Gas Properties The Company follows the successful efforts method of accounting for its oil and gas properties. Under this method of accounting, exploration costs such as exploratory geological and geophysical costs, delay rentals, and exploration overhead are expensed as incurred. All costs related to production, general corporate overhead, and similar activities are expensed as incurred. If an exploratory well provides evidence to justify potential development of reserves, drilling costs associated with the well are initially capitalized, or suspended, pending a determination as to whether a commercially sufficient quantity of proved reserves can be attributed to the area as a result of drilling. At the end of each quarter, management reviews the status of all suspended exploratory well costs in light of ongoing exploration activities; in particular, whether the Company is making sufficient progress in its ongoing exploration and appraisal efforts. If management determines that future appraisal drilling or development activities are unlikely to occur, associated suspended exploratory well costs are expensed. Unproved properties are assessed for impairment at least annually and are transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Unproved properties are assessed for impairment based on the Company’s current exploration plans. Costs of expired or abandoned leases are charged to exploration expense, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties, as well as impairment of unsuccessful leases, are included in exploration costs in the consolidated statements of operations. Costs to develop proved reserves, including the costs of all development wells and related equipment used in the production of crude oil and natural gas, are capitalized. Depreciation of the cost of proved oil and gas properties is calculated using the unit-of-production method ("UOP"). The UOP calculation multiplies the percentage of estimated proved reserves produced each quarter by the carrying value of those reserves. The reserve base used to calculate depreciation for leasehold acquisition costs and the cost to acquire proved properties is the sum of proved developed reserves and proved undeveloped reserves. The reserve base used to calculate the depreciation for capitalized costs for exploratory and development wells is the sum of proved developed reserves only. Estimated future dismantlement, restoration and abandonment costs, net of salvage values, are included in the depreciable cost. Oil and gas properties are grouped for depreciation in accordance with the Accounting Standards Codification ("ASC") ASC 932 "Extractive Activities—Oil and Gas” ("ASC 932"). The basis for grouping is a reasonable aggregation of properties with a common geological structural feature or stratigraphic condition, such as a reservoir or field. When circumstances indicate that proved oil and gas properties may be impaired, the Company compares unamortized capitalized costs to the expected undiscounted pre-tax future cash flows for the associated assets grouped at the lowest level for which identifiable cash flows are independent of cash flows of other assets. If the expected undiscounted pre-tax future cash flows, based on the Company’s estimate of future crude oil and natural gas prices, operating costs, anticipated production from proved reserves and other relevant data, are lower than the unamortized capitalized cost, the capitalized cost is reduced to fair value. Fair value is generally estimated using the income approach described in the ASC 820, "Fair Value Measurements" ("ASC 820"). If applicable, the Company utilizes prices and other relevant information generated by market transactions involving assets and liabilities that are identical or comparable to the item being measured as the basis for determining fair value. The expected future cash flows used for impairment reviews and related fair value calculations are typically based on judgmental assessments of future production volumes, commodity prices, operating costs, and capital investment plans, considering all available information at the date of review. These assumptions are applied to develop future cash flow projections that are then discounted to estimated fair value, using a discount rate believed to be consistent with those applied by market participants.
Asset Retirement Costs and Obligations	Asset Retirement Costs and Obligations Asset retirement obligations represent the present value of the estimated cash flows expected to be incurred to plug, abandon and remediate producing properties, excluding salvage values, at the end of their productive lives in accordance with applicable laws. The significant unobservable inputs to this fair value measurement include estimates of plugging, abandonment and remediation costs, well life, inflation and credit-adjusted risk-free rate. The inputs are calculated based on historical data as well as current estimates. When the liability is initially recorded, the carrying amount of the related long-lived asset is increased. Over time, accretion of the liability is recognized each period, and the capitalized cost is amortized over the useful life of the related asset and is included in "Depreciation, depletion and amortization" in the Company’s consolidated statements of operations. To estimate the fair value of an asset retirement obligation, the Company employs a present value technique, which reflects certain assumptions, including its credit‑adjusted risk‑free interest rate, inflation rate, the estimated settlement date of the liability and the estimated current cost to settle the liability. Changes in timing or to the original estimate of cash flows will result in change to the carrying amount of the liability and related long lived asset.
Intangible Asset	Intangible Asset (Successor) Concurrent with the closing of the Business Combination, the Company and EnerVest entered into a Non-Compete (the "Non-Compete") pursuant to which EnerVest and certain of its affiliates are restricted from competing with the Company in certain counties comprising the Eagle Ford Shale. The Company recorded an estimated cost of $44.4 million for the Non-Compete as an intangible asset on the consolidated balance sheet of the Successor. This intangible asset has a definite life and is subject to amortization utilizing straight line method over its economic life, currently estimated to be two and a half to four years. Magnolia assesses intangible assets for impairment together with related underlying long-lived assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment is recognized in the consolidated statements of operations if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value. For the period ended September 30, 2018, no impairment was recorded. For more discussion on the Non-Compete, refer to Note 6 - Intangible Asset.
Fair Value Measurements	Fair Value Measurements ASC 820 establishes a fair value hierarchy that prioritizes and ranks the level of observability of inputs used to measure investments at fair value. The observability of inputs is impacted by a number of factors, including the type of investment, characteristics specific to the investment, market conditions and other factors. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level I measurements) and the lowest priority to unobservable inputs (Level III measurements). Investments with readily available quoted prices or for which fair value can be measured from quoted prices in active markets will typically have a higher degree of input observability and a lesser degree of judgment applied in determining fair value. The three levels of the fair value hierarchy under ASC 820 are as follows: Level I—Quoted prices (unadjusted) in active markets for identical investments at the measurement date are used. Level II—Pricing inputs are other than quoted prices included within Level I that are observable for the investment, either directly or indirectly. Level II pricing inputs include quoted prices for similar investments in active markets, quoted prices for identical or similar investments in markets that are not active, inputs other than quoted prices that are observable for the investment, and inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level III—Pricing inputs are unobservable and include situations where there is little, if any, market activity for the investment. The inputs used in determination of fair value require significant judgment and estimation. In some cases, the inputs used to measure fair value might fall within different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the investment is categorized in its entirety is determined based on the lowest level input that is significant to the investment. Assessing the significance of a particular input to the valuation of an investment in its entirety requires judgment and considers factors specific to the investment. The categorization of an investment within the hierarchy is based upon the pricing transparency of the investment and does not necessarily correspond to the perceived risk of that investment.
Equity Method Investment	Equity Method Investment As part of the Business Combination, the Company acquired the Ironwood Interests . The Company accounts for its investment in Ironwood using the equity method of accounting. Accordingly, the Company recognizes its proportionate share of Ironwood’s net income in the consolidated statements of operations as “Income from equity method investee”. Any distributions by Ironwood would decrease the Company’s investment in Ironwood. The Company evaluates its investment in Ironwood for potential impairment whenever events or changes in circumstances indicate that there may be a loss in the value of Ironwood that was other than temporary.
Income Taxes	Income Taxes (Successor) Under ASC 740, “Income Taxes,” deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to net operating losses, tax credits, and temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period of the enactment date. Valuation allowances are established when it is more likely than not that some or all of the deferred tax assets will not be realized. The Company reports a liability or a reduction of deferred tax assets for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. When applicable, the Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense.
Purchase Price Allocation	Purchase Price Allocation Accounting for the acquisition of a business requires the allocation of the purchase price to the various assets and liabilities of the acquired business and recording deferred taxes for any differences between the allocated values and tax basis of assets and liabilities. Any excess of the purchase price over the amounts assigned to assets and liabilities is recorded as goodwill. The purchase price allocation is accomplished by recording each asset and liability at its estimated fair value. Estimated deferred taxes are based on available information concerning the tax basis of the acquired company’s assets and liabilities and tax-related carryforwards at the merger date, although such estimates may change in the future as additional information becomes known. The amount of goodwill recorded in any particular Business Combination can vary significantly depending upon the values attributed to assets acquired and liabilities assumed relative to the total acquisition cost. When estimating the fair values of assets acquired and liabilities assumed, the Company must apply various assumptions. The most significant assumptions relate to the estimated fair values assigned to proved and unproved crude oil and natural gas properties. To estimate the fair values of these properties, the Company prepares estimates of crude oil and natural gas reserves. Estimated fair values assigned to assets acquired can have a significant effect on results of operations in the future.
Commitments and Contingencies	Commitments and Contingencies Accruals for loss contingencies arising from claims, assessments, litigation, environmental and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted as additional information becomes available or circumstances change. Refer to Note 13 - Commitments and Contingencies for additional information.
Revenue Recognition	Revenue Recognition Oil and gas revenues are recognized when production is sold to a purchaser at a fixed or determinable price, when delivery has occurred and title has transferred, and if collectability of the revenue is probable. Cash received relating to future revenues is deferred and recognized when all revenue recognition criteria are met. The Company follows the sales method of accounting for crude oil and natural gas production imbalances and would recognize a liability if Magnolia's existing proved reserves were not adequate to cover an imbalance. Imbalances have not been significant in the periods presented.
Net Income Per Share of Common Stock	Net Income Per Share of Common Stock Basic earnings per common share is calculated by dividing net income attributable to Class A Common Stock by the weighted average number of shares of Class A Common Stock outstanding each period. Diluted earnings per share adds to those shares the incremental shares that would have been outstanding assuming exchanges of the Company's outstanding Class B Common Stock and warrants for Class A Common Stock. An anti-dilutive impact is an increase in earnings per share or a reduction in net loss per share resulting from the conversion, exercise, or contingent issuance of certain securities. The Company uses the "if-converted" method to determine the potential dilutive effect of conversions of its outstanding Class B Common Stock and the treasury stock method to determine the potential dilutive effect of its outstanding warrants exercisable for shares of Class A Common Stock. Refer to Note 11 - Earnings Per Share for additional information and the calculation of net earnings per share.
Recent Accounting Pronouncements	Recent Accounting Pronouncements (Successor) In February 2016, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2016–02, Leases (Topic 842), which will require lessees to recognize a right of use asset and a lease liability on their balance sheet for all leases, including operating leases, with a term of greater than 12 months. Currently the guidance would be applied using a modified retrospective transition method, which requires applying the new guidance to leases that exist or are entered into after the beginning of the earliest period in the financial statements. However, in July 2018, the FASB issued ASU 2018-11, which adds a transition option permitting entities to apply the provisions of the new standard at its adoption date instead of the earliest comparative period presented in the consolidated financial statements. Under this transition option, comparative reporting would not be required, and the provisions of the standard would be applied prospectively to leases in effect at the date of adoption. The standard will be effective for interim and annual periods beginning after December 15, 2018 for public companies and annual periods beginning after December 15, 2019 for all other entities, with earlier adoption permitted. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on January 1, 2019, using the optional transition method provided by ASU 2018-11. The Company is the lessee under various agreements for real estate, vehicles, and field equipment that are currently accounted for as operating leases. The Company has preliminarily determined its portfolio of leased assets and is reviewing all related contracts to determine the impact the adoption will have on its consolidated financial statements. While the Company has yet to finalize the estimated impact this standard will have on the consolidated financial statements, the adoption is anticipated to result in an increase in both assets and liabilities related to the Company's leases. In May 2014, the FASB issued ASU No. 2014–09, Revenue from Contracts with Customers. This ASU, as amended, superseded virtually all of the revenue recognition guidance in generally accepted accounting principles in the United States. The core principle of the five–step model is that an entity will recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on December 31, 2018 , using a modified retrospective approach. Upon initial evaluation of contracts in each of the Company’s revenue streams, the Company does not expect the adoption of this ASU to have a material impact on its consolidated financial statements. The Company continues to evaluate contracts against the requirements of the standard and is evaluating the disclosure requirements and assessing changes to the relevant business processes and the control activities within them as a result of the provisions of this ASU. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows: Classification of Certain Cash". Receipts and Cash Payments (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statements of cash flows. ASU 2016-15 is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017 for public companies and for fiscal years beginning after December 15, 2018 for all other entities. It is expected that the Company will cease to be an emerging growth company by December 31, 2018 and will adopt the standard on December 31, 2018. The adoption of this guidance will not impact the Company's financial position or results of operations but could result in presentation changes on Magnolia's consolidated statements of cash flows. In January 2017, the FASB issued ASU 2017-01 "Business Combinations (Topic 805): Clarifying the Definition of a Business" ("ASU 2017-01"), which clarifies the definition of a business to provide guidance in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 provides a screen to determine when a set of assets is not a business, requiring that when substantially all fair value of gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar identifiable assets, the set of assets is not a business. A framework is provided to assist in evaluating whether both an input and a substantive process are present for the set to be a business. ASU 2017-01 is effective for interim and annual periods after December 15, 2017 for public companies and annual periods beginning after December 15, 2018 for all other entities. No disclosures are required at transition. The Company early adopted ASU 2017-01 upon the closing of the Business Combination. There was no material impact to the Company's financial statements as a result of this adoption, however the new standard may result in more transactions being accounted for as acquisitions (and dispositions) of assets rather than businesses in the future.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Purchase Consideration for Business Combination	The purchase consideration for the Business Combination was as follows: At July 31, Preliminary Purchase Consideration: Cash consideration $ 1,219,217 Stock consideration (1) 1,423,483 Fair value of contingent earnout purchase consideration (2) 169,000 Total purchase price consideration $ 2,811,700 (1) At closing of the Business Combination, the Karnes County Contributors received 83.9 million shares of Class B Common Stock and 31.8 million shares of Class A Common Stock. (2) Pursuant to ASC 805, ASC 480, "Distinguishing Liabilities from Equity" and ASC 815, "Derivatives and Hedging", the Karnes County earnout consideration has been valued at fair value as of the Closing Date and has been classified in stockholders’ equity. The Giddings earnout has been valued at fair value as of the Closing Date and has been classified as a liability. The fair value of the earnouts was determined using the Monte Carlo simulation valuation method based on Level 3 inputs in the fair value hierarchy.
Summary of Allocation of Purchase Consideration to Assets and Liabilities Assumed	The recognized fair value of identifiable assets and acquired liabilities assumed in connection with the Subsequent GulfTex Acquisition, is as follows: (In thousands) Total consideration $ 150,139 Purchase price allocation: Accounts receivable 10,501 Proved oil and natural gas properties 118,572 Unproved oil and natural gas properties 22,802 Accounts payable and accrued liabilities (1,679 ) Asset retirement obligations (57 ) $ 150,139 The following table summarizes the allocation of the purchase consideration to the assets and liabilities assumed: At August 31, 2018 (in thousands) Estimated fair value of assets acquired Other current assets $ 1,290 Oil & gas properties (1) 200,035 Total fair value of assets acquired 201,325 Estimated fair value of liabilities assumed Asset retirement obligation and other current liabilities (9,812 ) Fair value of net assets acquired $ 191,513 (1) The fair value measurements of oil and natural gas properties and asset retirement obligations are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair values of oil and natural gas properties and asset retirement obligations were measured using valuation techniques that convert future cash flows to a single discounted amount. Significant inputs to the valuation of oil and natural gas properties included estimates of: (i) recoverable reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices; and (v) a market-based weighted average cost of capital rate. These inputs required significant judgments and estimates by management at the time of the valuation and may be subject to change. The following table summarizes the allocation of the purchase consideration to the assets and liabilities assumed: At July 31, 2018 (in thousands) Estimated fair value of assets acquired Account receivable $ 89,674 Other current assets 2,853 Oil & gas properties (1) 2,800,258 Ironwood equity investment 18,100 Total fair value of assets acquired 2,910,885 Estimated fair value of liabilities assumed Accounts payable and other current liabilities (56,315 ) Asset retirement obligation (34,132 ) Deferred tax liability (8,738 ) Fair value of net assets acquired $ 2,811,700 (1) The fair value measurements of oil and natural gas properties and asset retirement obligations are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair values of oil and natural gas properties and asset retirement obligations were measured using valuation techniques that convert future cash flows to a single discounted amount. Significant inputs to the valuation of oil and natural gas properties included estimates of: (i) recoverable reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices; and (v) a market-based weighted average cost of capital rate. These inputs required significant judgments and estimates by management at the time of the valuation and may be subject to change. The recognized fair value of identifiable assets and acquired liabilities assumed in connection with the Subsequent BlackBrush Acquisition, is as follows: (In thousands) Total consideration $ 58,653 Purchase price allocation: Accounts receivable 2,193 Proved oil and natural gas properties 57,263 Unproved oil and natural gas properties 1,552 Accounts payable and accrued liabilities (2,244 ) Asset retirement obligations (111 ) $ 58,653
Schedule of Pro Forma Combined Financial Information	The pro forma combined financial information has been included for comparative purposes and is not necessarily indicative of the results that might have actually occurred had the Business Combination taken place on January 1, 2017; furthermore, the financial information is not intended to be a projection of future results. (Unaudited Pro Forma) (in thousands) Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 Total Revenues $ 267,659 $ 110,294 $ 723,768 $ 356,254 Net income attributable to Class A Common Stock 57,891 6,531 151,316 26,257 Income per share - basic 0.39 0.04 1.02 0.21 Income per share - diluted 0.38 0.04 0.98 0.20

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Predecessor) (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Values and Classification of Outstanding Derivative Assets	The following table sets forth the fair values and classification of the outstanding derivatives entered into by the Karnes County Contributors, on behalf of the Predecessor, as of December 31, 2017 : (In thousands) Gross Amounts of Recognized Assets Gross Amounts of Offset in the Balance Sheet Net Amounts Of Assets Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative asset $ 180 $ (180 ) $ — Long-term derivative asset 48 (48 ) — Total $ 228 $ (228 ) $ — Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts Of Liabilities Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative liability $ 6,944 $ (180 ) $ 6,764 Long-term derivative liability 3,100 (48 ) 3,052 Total $ 10,044 $ (228 ) $ 9,816
Fair Values and Classification of Outstanding Derivative Liabilities	The following table sets forth the fair values and classification of the outstanding derivatives entered into by the Karnes County Contributors, on behalf of the Predecessor, as of December 31, 2017 : (In thousands) Gross Amounts of Recognized Assets Gross Amounts of Offset in the Balance Sheet Net Amounts Of Assets Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative asset $ 180 $ (180 ) $ — Long-term derivative asset 48 (48 ) — Total $ 228 $ (228 ) $ — Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts Of Liabilities Presented in the Balance Sheet Derivatives As of December 31, 2017 (Predecessor): Derivative liability $ 6,944 $ (180 ) $ 6,764 Long-term derivative liability 3,100 (48 ) 3,052 Total $ 10,044 $ (228 ) $ 9,816

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value Hierarchy for Assets and Liabilities Required to be Measured at Fair Value on a Recurring Basis	The following table presents the fair value hierarchy table for the Predecessor’s assets and liabilities that are required to be measured at fair value on a recurring basis: (In thousands) Level 1 Level 2 Level 3 Total Fair Value As of December 31, 2017 (Predecessor): Assets: Oil, natural gas and natural gas liquids derivatives $ — $ 228 $ — $ 228 Liabilities: Oil, natural gas and natural gas liquids derivatives $ — $ 10,044 $ — $ 10,044
Schedule of Carrying Values and Fair Values of Financial Instruments Not Carried at Fair Value	Carrying values and fair values of financial instruments that are not carried at fair value in the accompanying consolidated balance sheets as of September 30, 2018 is as follows: September 30, 2018 (In thousands) Carrying Value Fair Value Long-term debt $ 388,343 $ 399,000

Intangible Asset (Tables)

Intangible Asset (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Asset	(In thousands) September 30, 2018 (Successor) Non-Compete Intangible Asset $ 44,400 Accumulated amortization (2,417 ) Intangible, net $ 41,983 Weighted average amortization (years) 3.25

Asset Retirement Obligation (Ta

Asset Retirement Obligation (Tables)	9 Months Ended
	Sep. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Summary of Changes in Asset Retirement Obligations	A summary of the changes in asset retirement obligations is included in the table below: (In thousands) 2018 Balance, as of January 1 (Predecessor) $ 3,929 Liabilities incurred and assumed through acquisitions 553 Liabilities settled (85 ) Accretion expense 104 Balance, as of July 30 (Predecessor) $ 4,501 Balance, as of July 31 (Successor) $ — Liabilities incurred and assumed through acquisitions 43,930 Liabilities settled — Accretion expense 391 Balance, as of September 30 (Successor) 44,321 Less: Current portion (884 ) Long-term portion $ 43,437

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Components of Income Tax Provision (Benefit)	The Company's income tax provision (benefit) consisted of the following components: (In thousands) Successor Predecessor July 31, 2018 through September 30, 2018 July 1, 2018 through July 30, 2018 January 1, 2018 through July 30, 2018 Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Current: Federal $ — $ — $ — $ — $ — State 45 631 1,461 81 848 45 631 1,461 81 848 Deferred: Federal 3,493 — — — — State — 135 324 549 1,119 3,493 135 324 549 1,119 Total provision $ 3,538 $ 766 $ 1,785 $ 630 $ 1,967

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Components of Debt	The Company's debt is comprised of the following: (In thousands) Successor September 30, 2018 Revolving credit facility $ — 6.0% Senior Notes due 2026 400,000 Total long-term debt 400,000 Less: unamortized deferred financing cost (11,657 ) Total debt, net $ 388,343

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Reconciliation of Numerators and Denominators for Basic and Diluted Per Share Computation	A reconciliation of the numerators and denominators of the basic and diluted per share computations follows. No such computation is necessary for the Predecessor periods as the Predecessor was not previously accounted for as a standalone legal entity and did not have publicly traded shares. Successor (In thousands) July 31, 2018 through September 30, 2018 Basic: Net Income attributable to Class A Common Stock $ 6,708 Weighted average number of common shares outstanding during the period 151,992 Net income per common share - basic $ 0.04 Diluted: Net Income attributable to Class A Common Stock $ 6,708 Basic weighted average number of common shares outstanding during the period 151,992 Add: Dilutive effect of warrants 5,080 Diluted weighted average number of common shares outstanding during the period 157,072 Net income per common share - diluted $ 0.04

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Contractual Obligations for Long-term Operating Leases and Purchase Obligations	At September 30, 2018 , contractual obligations for long-term operating leases and purchase obligations are as follows: Net Minimum Commitments (in thousands) Remainder of 2018 2019 2020 2021 2022 Thereafter Total Purchase obligations (1) $ 7,977 $ 14,641 $ 2,346 $ 131 $ 131 $ 241 $ 25,467 Operating lease obligations (2) 109 436 274 44 — — 863 Service fee commitment (3) 5,891 23,564 13,745 — — — 43,200 Total Net Minimum Commitments $ 13,977 $ 38,641 $ 16,365 $ 175 $ 131 $ 241 $ 69,530 (1) Amounts represent any agreements to purchase goods or services that are enforceable and legally binding and that specify all significant terms. These include minimum commitments associated with firm transportation contracts and frac sand commitments. (2) Amounts include long-term lease payments for compressors, vehicles and office space. (3) On the Closing Date, the Company and EVOC entered into a Services Agreement (the "Services Agreement"), pursuant to which EVOC, under the direction of the Company’s management, will provide the Company's services identical to the services historically provided by EVOC in operating the Acquired Assets, including administrative, back office and day-to-day field level services reasonably necessary to operate the business of the Company and its assets, subject to certain exceptions. As consideration for the services to be provided under the Services Agreement, the Company will pay EVOC a fixed annual services fee of approximately $23.6 million . The annual services fee may be (a) increased or decreased to account for asset acquisitions and dispositions of assets, (b) increased to account for an increase in the rig count attributable to the assets and (c) decreased if the Company must perform any of such services itself because EVOC is unable or fails to do so. The term of the Services Agreement is five years , but the Services Agreement is subject to termination by either party after two years .

Description of Business and B_2

Description of Business and Basis of Presentation - Narrative (Details) $ / shares in Units, shares in Millions	Jul. 31, 2018USD ($)$ / sharesshares	Mar. 15, 2018subsidiary	Sep. 30, 2018USD ($)$ / shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of indirect wholly owned subsidiaries formed | subsidiary		3
Senior Notes | 6.0% Senior Notes due 2026
Business Acquisition [Line Items]
Aggregate principal amount of debt issued and sold | $	$ 400,000,000
Stated interest rate	6.00%		6.00%
Class A Common Stock
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001
Class B Common Stock
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001
Business Combination
Business Acquisition [Line Items]
Aggregate consideration, cash | $	$ 1,219,217,000		$ 1,219,217,000
Business Combination | Class A Common Stock
Business Acquisition [Line Items]
Aggregate consideration, common stock (in shares)	31.8
Business Combination | Class A Common Stock | Private Placement
Business Acquisition [Line Items]
Shares issued and sold (in shares)	35.5
Gross proceeds from shares issued and sold | $	$ 355,000,000
Business Combination | Class B Common Stock
Business Acquisition [Line Items]
Aggregate consideration, common stock (in shares)	83.9
Business Combination | Magnolia LLC Units
Business Acquisition [Line Items]
Aggregate consideration, common stock (in shares)	83.9
Ironwood
Business Acquisition [Line Items]
Percentage of membership interest	35.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Narrative (Details)	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Variable Interest Entity, Primary Beneficiary | Magnolia LLC
Variable Interest Entity [Line Items]
Percentage of economic interest	63.20%
Percentage of economic interest owned by noncontrolling interest holders	36.80%	36.80%
Non-Compete Agreement
Finite-Lived Intangible Assets [Line Items]
Estimated cost of intangible asset	$ 44,400,000	$ 44,400,000
Impairment recorded		$ 0
Non-Compete Agreement | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		2 years 6 months
Non-Compete Agreement | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		4 years

Acquisitions - Narrative (Deta

Acquisitions - Narrative (Details) $ in Thousands

Oct. 04, 2018shares

Sep. 28, 2018USD ($)

Aug. 31, 2018USD ($)shares

Jul. 31, 2018USD ($)shares

Mar. 01, 2018USD ($)

Jan. 31, 2017USD ($)

Jul. 30, 2018USD ($)

Sep. 30, 2018USD ($)trancheshares

Sep. 30, 2017USD ($)

Jul. 30, 2018USD ($)

Sep. 30, 2017USD ($)

Sep. 30, 2018USD ($)tranche

Business Acquisition [Line Items]

Cash payment to fully settle earnout obligation

$ 26,000

Loss related to settlement of Giddings earnout obligation

(6,700)

Transaction costs incurred

$ 22,366

Predecessor

Business Acquisition [Line Items]

Cash payment to fully settle earnout obligation

$ 0

$ 0

Loss related to settlement of Giddings earnout obligation

0

0

Transaction costs incurred

$ 0

$ 0

0

0

Non-Compete Agreement | Minimum

Business Acquisition [Line Items]

Estimated economic life of intangible asset

2 years 6 months

Non-Compete Agreement | Maximum

Business Acquisition [Line Items]

Estimated economic life of intangible asset

4 years

Class B Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche III | Subsequent Event

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

2,900,000

Class A Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche III | Subsequent Event

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

1,100,000

EnerVest Business Combination

Business Acquisition [Line Items]

Cash consideration

$ 1,219,217

$ 1,219,217

Loss related to settlement of Giddings earnout obligation

6,700

Transaction costs incurred

22,400

$ 34,300

Debt issuance costs incurred in connection with consummation of Business Combination

23,500

One time purchase of seismic licenses

$ 11,000

Total purchase price consideration

$ 2,811,700

EnerVest Business Combination | Predecessor

Business Acquisition [Line Items]

Cash consideration

$ 0

$ 0

EnerVest Business Combination | Non-Compete Agreement | Minimum

Business Acquisition [Line Items]

Estimated economic life of intangible asset

2 years 6 months

EnerVest Business Combination | Non-Compete Agreement | Maximum

Business Acquisition [Line Items]

Estimated economic life of intangible asset

4 years

EnerVest Business Combination | Giddings Purchase Agreement | Affiliate

Business Acquisition [Line Items]

Loss related to settlement of Giddings earnout obligation

$ 6,700

EnerVest Business Combination | Class B Common Stock

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

83,900,000

EnerVest Business Combination | Magnolia LLC Units

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

83,900,000

EnerVest Business Combination | Class A Common Stock

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

31,800,000

EnerVest Business Combination | Class A Common Stock | Affiliate

Business Acquisition [Line Items]

Number of shares authorized for issuance based on achievement of certain stock price thresholds (in shares) | shares

4,000,000

EnerVest Business Combination | Karnes County Contributors

Business Acquisition [Line Items]

Cash consideration

$ 911,500

EnerVest Business Combination | Karnes County Contributors | Karnes County Contribution Agreement | Affiliate

Business Acquisition [Line Items]

Term of contribution agreement

5 years

Number of tranches | tranche

3

3

EnerVest Business Combination | Karnes County Contributors | Earnout Shares | Karnes County Contribution Agreement | Affiliate

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

13,000,000

EnerVest Business Combination | Karnes County Contributors | Class B Common Stock

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

83,900,000

EnerVest Business Combination | Karnes County Contributors | Class B Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche I and Tranche II

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

6,500,000

EnerVest Business Combination | Karnes County Contributors | Class B Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche III | Subsequent Event

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

2,900,000

EnerVest Business Combination | Karnes County Contributors | Magnolia LLC Units

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

83,900,000

EnerVest Business Combination | Karnes County Contributors | Class B Common Stock together with Magnolia LLC Units | Exchange of Class B Common Stock and Magnolia LLC Units for Class A Common Stock

Business Acquisition [Line Items]

Exchange ratio for equity interests issued

1

EnerVest Business Combination | Karnes County Contributors | Class A Common Stock

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

31,800,000

EnerVest Business Combination | Karnes County Contributors | Class A Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche I and Tranche II

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

2,500,000

EnerVest Business Combination | Karnes County Contributors | Class A Common Stock | Karnes County Contribution Agreement | Affiliate | Tranche III | Subsequent Event

Business Acquisition [Line Items]

Additional shares issued upon meeting stock price thresholds (in shares) | shares

1,100,000

EnerVest Business Combination | Giddings Sellers

Business Acquisition [Line Items]

Cash consideration

$ 282,700

EnerVest Business Combination | Giddings Sellers | Giddings Purchase Agreement | Affiliate

Business Acquisition [Line Items]

Aggregate amount of cash earnout payments authorized

47,000

Cash payment to fully settle earnout obligation

$ 26,000

EnerVest Business Combination | Ironwood Sellers

Business Acquisition [Line Items]

Cash consideration

$ 25,000

Harvest Acquisition

Business Acquisition [Line Items]

Cash consideration

$ 133,300

Total purchase price consideration

$ 191,500

Harvest Acquisition | Class A Common Stock

Business Acquisition [Line Items]

Equity interests issued in business combination (in shares) | shares

4,200,000

GulfTex Acquisition | Predecessor

Business Acquisition [Line Items]

Total purchase price consideration

$ 150,139

BlackBrush Acquisition | Predecessor

Business Acquisition [Line Items]

Total purchase price consideration

$ 58,653

Acquisitions - Schedule of Pur

Acquisitions - Schedule of Purchase Consideration for Business Combination (Details) - USD ($) $ in Thousands, shares in Millions	Jul. 31, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Stock consideration		$ 1,481,695
EnerVest Business Combination
Business Acquisition [Line Items]
Cash consideration	$ 1,219,217	$ 1,219,217
Stock consideration	1,423,483
Fair value of contingent earnout purchase consideration	169,000
Total purchase price consideration	2,811,700
EnerVest Business Combination | Karnes County Contributors
Business Acquisition [Line Items]
Cash consideration	$ 911,500
EnerVest Business Combination | Class B Common Stock
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)	83.9
EnerVest Business Combination | Class B Common Stock | Karnes County Contributors
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)	83.9
EnerVest Business Combination | Class A Common Stock
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)	31.8
EnerVest Business Combination | Class A Common Stock | Karnes County Contributors
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)	31.8

Acquisitions - Summary of Allo

Acquisitions - Summary of Allocation of Purchase Consideration to Assets and Liabilities Assumed (Details) - USD ($) $ in Thousands	Aug. 31, 2018	Jul. 31, 2018	Mar. 01, 2018	Jan. 31, 2017
EnerVest Business Combination
Business Acquisition [Line Items]
Total consideration		$ 2,811,700
Estimated fair value of assets acquired
Account receivable		89,674
Other current assets		2,853
Oil & gas properties		2,800,258
Ironwood equity investment		18,100
Total fair value of assets acquired		2,910,885
Estimated fair value of liabilities assumed
Accounts payable and other current liabilities		(56,315)
Asset retirement obligation and other current liabilities		(34,132)
Deferred tax liability		(8,738)
Fair value of net assets acquired		$ 2,811,700
Harvest Acquisition
Business Acquisition [Line Items]
Total consideration	$ 191,500
Estimated fair value of assets acquired
Other current assets	1,290
Oil & gas properties	200,035
Total fair value of assets acquired	201,325
Estimated fair value of liabilities assumed
Asset retirement obligation and other current liabilities	(9,812)
Fair value of net assets acquired	$ 191,513
GulfTex Acquisition | Predecessor
Business Acquisition [Line Items]
Total consideration			$ 150,139
Estimated fair value of assets acquired
Account receivable			10,501
Proved oil and natural gas properties			118,572
Unproved oil and natural gas properties			22,802
Estimated fair value of liabilities assumed
Accounts payable and other current liabilities			(1,679)
Asset retirement obligation and other current liabilities			(57)
Fair value of net assets acquired			$ 150,139
BlackBrush Acquisition | Predecessor
Business Acquisition [Line Items]
Total consideration				$ 58,653
Estimated fair value of assets acquired
Account receivable				2,193
Proved oil and natural gas properties				57,263
Unproved oil and natural gas properties				1,552
Estimated fair value of liabilities assumed
Accounts payable and other current liabilities				(2,244)
Asset retirement obligation and other current liabilities				(111)
Fair value of net assets acquired				$ 58,653

Acquisitions - Schedule of Pro

Acquisitions - Schedule of Pro Forma Combined Financial Information (Details) - EnerVest Business Combination - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Total Revenues	$ 267,659	$ 110,294	$ 723,768	$ 356,254
Net income attributable to Class A Common Stock	$ 57,891	$ 6,531	$ 151,316	$ 26,257
Income per share - basic (in dollars per share)	$ 0.39	$ 0.04	$ 1.02	$ 0.21
Income per share - diluted (in dollars per share)	$ 0.38	$ 0.04	$ 0.98	$ 0.20

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Predecessor) - Narrative (Details) - USD ($) $ in Thousands	2 Months Ended	7 Months Ended	9 Months Ended
	Sep. 30, 2018	Jul. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Total cash settlement payments	$ 0
Predecessor
Derivative [Line Items]
Total cash settlement payments		$ 27,617	$ (52)

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities (Predecessor) - Fair Values and Classification of Outstanding Derivatives (Details) - Predecessor $ in Thousands	Dec. 31, 2017USD ($)
Derivatives
Gross Amounts of Recognized Assets	$ 228
Gross Amounts of Offset in the Balance Sheet	(228)
Net Amounts Of Assets Presented in the Balance Sheet	0
Derivatives
Gross Amounts of Recognized Liabilities	10,044
Gross Amounts Offset in the Balance Sheet	(228)
Net Amounts Of Liabilities Presented in the Balance Sheet	9,816
Derivative asset
Derivatives
Gross Amounts of Recognized Assets	180
Gross Amounts of Offset in the Balance Sheet	(180)
Net Amounts Of Assets Presented in the Balance Sheet	0
Long-term derivative asset
Derivatives
Gross Amounts of Recognized Assets	48
Gross Amounts of Offset in the Balance Sheet	(48)
Net Amounts Of Assets Presented in the Balance Sheet	0
Derivative liability
Derivatives
Gross Amounts of Recognized Liabilities	6,944
Gross Amounts Offset in the Balance Sheet	(180)
Net Amounts Of Liabilities Presented in the Balance Sheet	6,764
Long-term derivative liability
Derivatives
Gross Amounts of Recognized Liabilities	3,100
Gross Amounts Offset in the Balance Sheet	(48)
Net Amounts Of Liabilities Presented in the Balance Sheet	$ 3,052

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Hierarchy (Details) - Predecessor $ in Thousands	Dec. 31, 2017USD ($)
Assets:
Oil, natural gas and natural gas liquids derivatives	$ 0
Liabilities:
Oil, natural gas and natural gas liquids derivatives	9,816
Recurring
Assets:
Oil, natural gas and natural gas liquids derivatives	228
Liabilities:
Oil, natural gas and natural gas liquids derivatives	10,044
Recurring | Level 1
Assets:
Oil, natural gas and natural gas liquids derivatives	0
Liabilities:
Oil, natural gas and natural gas liquids derivatives	0
Recurring | Level 2
Assets:
Oil, natural gas and natural gas liquids derivatives	228
Liabilities:
Oil, natural gas and natural gas liquids derivatives	10,044
Recurring | Level 3
Assets:
Oil, natural gas and natural gas liquids derivatives	0
Liabilities:
Oil, natural gas and natural gas liquids derivatives	$ 0

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments Not Carried at Fair Value (Details) - Level 1 $ in Thousands	Sep. 30, 2018USD ($)
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 388,343
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 399,000

Intangible Asset - Narrative (

Intangible Asset - Narrative (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Sep. 30, 2018
Non-Compete Agreement
Finite-Lived Intangible Assets [Line Items]
Estimated cost of intangible asset		$ 44,400
Non-Compete Agreement | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		2 years 6 months
Non-Compete Agreement | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		4 years
EnerVest properties | Non-Compete Agreement | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		2 years 6 months
EnerVest properties | Non-Compete Agreement | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		4 years
EnerVest properties | Class A Common Stock | Affiliate of EnerVest
Finite-Lived Intangible Assets [Line Items]
Number of shares authorized for issuance based on achievement of certain stock price thresholds (in shares)	4,000,000

Intangible Asset - Schedule of

Intangible Asset - Schedule of Intangible Asset (Details) $ in Thousands	2 Months Ended
	Sep. 30, 2018USD ($)
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (2,417)
Intangible, net	$ 41,983
Weighted average amortization (years)	3 years 3 months
Non-Compete Agreement
Finite-Lived Intangible Assets [Line Items]
Non-Compete Intangible Asset	$ 44,400

Asset Retirement Obligation -

Asset Retirement Obligation - Changes in Asset Retirement Obligations (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended		3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, as of beginning of period			$ 0
Liabilities incurred and assumed through acquisitions			43,930		$ 553
Liabilities settled			0
Accretion expense		$ 391	391
Balance, as of end of period		44,321	44,321
Less: Current portion		(884)	(884)
Long-term portion		43,437	$ 43,437
Predecessor
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, as of beginning of period		$ 4,501			3,929
Liabilities settled					(85)
Accretion expense	$ 21			$ 87	104	$ 175
Balance, as of end of period	$ 4,501				$ 4,501
Long-term portion							$ 3,929

Income Taxes - Narrative (Deta

Income Taxes - Narrative (Details)	2 Months Ended
	Sep. 30, 2018USD ($)
Income Tax Disclosure [Abstract]
United States federal income tax expense	$ 3,493,000
Annual effective tax rate	12.20%
Amount accrued for income tax uncertainties	$ 0
Amount accrued for income tax interest and penalties	$ 0

Income Taxes - Components of In

Income Taxes - Components of Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 30, 2018	Sep. 30, 2017
Current:
Federal		$ 0
State		45
Current income tax provision (benefit)		45
Deferred:
Federal		3,493
State		0
Deferred income tax provision (benefit)		3,493
Total provision		$ 3,538
Predecessor
Current:
Federal	$ 0		$ 0	$ 0	$ 0
State	631		81	1,461	848
Current income tax provision (benefit)	631		81	1,461	848
Deferred:
Federal	0		0	0	0
State	135		549	324	1,119
Deferred income tax provision (benefit)	135		549	324	1,119
Total provision	$ 766		$ 630	$ 1,785	$ 1,967

Long-Term Debt - Components of

Long-Term Debt - Components of Debt (Details) - USD ($)	Sep. 30, 2018	Jul. 31, 2018
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000
Less: unamortized deferred financing cost	(11,657,000)
Total debt, net	388,343,000
Line of Credit | Revolving credit facility
Debt Instrument [Line Items]
Total long-term debt	0
Senior Notes | 6.0% Senior Notes due 2026
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000
Stated interest rate	6.00%	6.00%

Long-Term Debt - Credit Facili

Long-Term Debt - Credit Facility Narrative (Details)	2 Months Ended
	Sep. 30, 2018USD ($)
Line of Credit Facility [Line Items]
Deferred financing costs	$ 11,657,000
Interest expense	4,959,000
Outstanding borrowings	400,000,000
Line of Credit | RBL Facility
Line of Credit Facility [Line Items]
Deferred financing costs incurred in connection with securing the RBL Facility	$ 11,700,000
Amortization period	5 years
Interest expense	$ 800,000
Outstanding borrowings	0
Line of Credit | RBL Facility | Magnolia Operating
Line of Credit Facility [Line Items]
Maximum commitments, aggregate principal amount	1,000,000,000
Initial borrowing base	$ 550,000,000
Leverage ratio	4
Leverage ratio, minimum threshold for current ratio	3
Current ratio	1
Line of Credit | Letter of Credit Sublimit | Magnolia Operating
Line of Credit Facility [Line Items]
Maximum commitments, aggregate principal amount	$ 100,000,000

Long-Term Debt - 2026 Senior N

Long-Term Debt - 2026 Senior Notes Narrative (Details) - USD ($)	2 Months Ended
	Sep. 30, 2018	Jul. 31, 2018
Debt Instrument [Line Items]
Interest expense	$ 4,959,000
Senior Notes | 6.0% Senior Notes due 2026
Debt Instrument [Line Items]
Aggregate principal amount		$ 400,000,000
Stated interest rate	6.00%	6.00%
Redemption price, percentage of principal amount of Notes redeemed	100.00%
Deferred financing costs incurred in connection with securing the 2026 Senior Notes	$ 11,800,000
Interest expense	$ 4,200,000

Stockholders' Equity and Pare_2

Stockholders' Equity and Parents' Net Investment - Narrative (Details) $ / shares in Units, $ in Thousands	Sep. 30, 2018vote$ / sharesshares	Sep. 30, 2018USD ($)voteday$ / sharesshares	Sep. 30, 2018USD ($)vote$ / sharesshares
Class of Stock [Line Items]
Warrants outstanding (in shares)	31,700,000	31,700,000	31,700,000
Transaction related costs | $		$ 22,366
Federal income tax expense | $		3,500
Business Combination
Class of Stock [Line Items]
Transaction related costs | $		$ 22,400	$ 34,300
Variable Interest Entity, Primary Beneficiary | Magnolia LLC
Class of Stock [Line Items]
Percentage of economic interest	63.20%
Percentage of economic interest owned by noncontrolling interest holders	36.80%	36.80%	36.80%
Public Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	21,700,000	21,700,000	21,700,000
Private Placement Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	10,000,000	10,000,000	10,000,000
Common Class A Warrant
Class of Stock [Line Items]
Number of shares each warrant entitles the holder to purchase (in shares)	1	1	1
Exercise price (in dollars per share) | $ / shares	$ 11.50	$ 11.50	$ 11.50
Common Class A Existing Warrant
Class of Stock [Line Items]
Redemption price (in dollars per share) | $ / shares	0.01	0.01	0.01
Minimum last sale price of common stock in order to redeem outstanding warrants at reduced rate (in dollars per share) | $ / shares	$ 18	$ 18	$ 18
Threshold trading days | day		20
Measurement period for threshold trading days, ending on the third business day before notice of redemption is sent to warrant holders | day		30
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	1,300,000,000	1,300,000,000	1,300,000,000
Common stock, shares issued (in shares)	155,227,284	155,227,284	155,227,284
Common stock, shares outstanding (in shares)	155,227,284	155,227,284	155,227,284
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	225,000,000	225,000,000	225,000,000
Common stock, shares issued (in shares)	90,452,174	90,452,174	90,452,174
Number of votes for each share held | vote	1	1	1
Common stock, shares outstanding (in shares)	90,452,174	90,452,174	90,452,174

Earnings Per Share - Reconcili

Earnings Per Share - Reconciliation of Numerators and Denominators for Basic and Diluted Per Share Computation (Details) $ / shares in Units, shares in Thousands, $ in Thousands	2 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Basic:
Net Income attributable to Class A Common Stock | $	$ 6,708
Weighted average number of common shares outstanding during the period (in shares) (in shares)	151,992
Net income per common share - basic (in dollars per share) | $ / shares	$ 0.04
Diluted:
Net Income attributable to Class A Common Stock | $	$ 6,708
Weighted average number of common shares outstanding during the period (in shares) (in shares)	151,992
Dilutive effect of warrants (in shares)	5,080
Diluted weighted average number of common shares outstanding during the period (in shares)	157,072
Net income per common share - diluted (in shares) | $ / shares	$ 0.04
Class A Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock issuable upon conversion of Class B Common Stock excluded due to effect being anti-dilutive (in shares)	87,600

Related Party Transactions - N

Related Party Transactions - Narrative (Details) $ in Thousands	Oct. 04, 2018shares	Jul. 31, 2018USD ($)directorshares	Jul. 30, 2018USD ($)	Sep. 30, 2018USD ($)trancheshares	Sep. 30, 2017USD ($)	Jul. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Related Party Transaction [Line Items]
Accounts receivable from EVOC and other related parties | $				$ 0
Predecessor
Related Party Transaction [Line Items]
Accounts receivable from EVOC and other related parties | $								$ 13,692
EnerVest Business Combination | Class B Common Stock
Related Party Transaction [Line Items]
Additional shares authorized for issuance (in shares)		83,900,000
EnerVest Business Combination | Class A Common Stock
Related Party Transaction [Line Items]
Additional shares authorized for issuance (in shares)		31,800,000
EnerVest Business Combination | Karnes County Contributors | Class B Common Stock
Related Party Transaction [Line Items]
Additional shares authorized for issuance (in shares)		83,900,000
EnerVest Business Combination | Karnes County Contributors | Class A Common Stock
Related Party Transaction [Line Items]
Additional shares authorized for issuance (in shares)		31,800,000
Registration Rights Agreement
Related Party Transaction [Line Items]
Number of independent directors prior to Business Combination | director		4
Affiliate | Stockholder Agreement | Karnes County Contributors
Related Party Transaction [Line Items]
Number of directors entitled to nominate to each committee of the Board | director		1
Affiliate | Stockholder Agreement | Sponsor
Related Party Transaction [Line Items]
Number of directors entitled to nominate to each committee of the Board | director		1
Affiliate | Stockholder Agreement | Higher End of Stock Ownership Threshold | Karnes County Contributors
Related Party Transaction [Line Items]
Number of directors entitled to nominate if lower stock ownership threshold is achieved | director		2
Higher stock ownership threshold		15.00%
Affiliate | Stockholder Agreement | Higher End of Stock Ownership Threshold | Sponsor
Related Party Transaction [Line Items]
Number of directors entitled to nominate if lower stock ownership threshold is achieved | director		2
Higher stock ownership threshold		60.00%
Affiliate | Stockholder Agreement | Lower End of Stock Ownership Threshold | Karnes County Contributors
Related Party Transaction [Line Items]
Number of directors entitled to nominate if lower stock ownership threshold is achieved | director		1
Lower stock ownership threshold		2.00%
Affiliate | Stockholder Agreement | Lower End of Stock Ownership Threshold | Sponsor
Related Party Transaction [Line Items]
Number of directors entitled to nominate if lower stock ownership threshold is achieved | director		1
Lower stock ownership threshold		25.00%
Affiliate | Karnes County Contribution Agreement | Class B Common Stock | Tranche III | Subsequent Event
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)	2,900,000
Affiliate | Karnes County Contribution Agreement | Class A Common Stock | Tranche III | Subsequent Event
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)	1,100,000
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors
Related Party Transaction [Line Items]
Term of contribution agreement		5 years
Number of tranches | tranche				3
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors | Class B Common Stock | Tranche III | Subsequent Event
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)	2,900,000
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors | Class B Common Stock | Tranche I and Tranche II
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)				6,500,000
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors | Class A Common Stock | Tranche III | Subsequent Event
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)	1,100,000
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors | Class A Common Stock | Tranche I and Tranche II
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares)				2,500,000
Affiliate | Karnes County Contribution Agreement | EnerVest Business Combination | Karnes County Contributors | Earnout Shares
Related Party Transaction [Line Items]
Additional shares authorized for issuance (in shares)		13,000,000
Affiliate | Sponsor Loan | Sponsor | Unsecured Promissory Note
Related Party Transaction [Line Items]
Repayment of unsecured promissory note | $		$ 1,000
Affiliate | Management Fees | Karnes County Contributors | Predecessor
Related Party Transaction [Line Items]
Related party transaction expenses | $			$ 1,500		$ 3,900	$ 9,800	$ 11,300

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Sep. 30, 2018
Purchase obligations
Remainder of 2018		$ 7,977
2,019		14,641
2,020		2,346
2,021		131
2,022		131
Thereafter		241
Purchase Obligation		25,467
Operating lease obligations
Remainder of 2018		109
2,019		436
2,020		274
2,021		44
2,022		0
Thereafter		0
Total		863
Service fee commitment
Remainder of 2018		5,891
2,019		23,564
2,020		13,745
2,021		0
2,022		0
Thereafter		0
Total		43,200
Total Net Minimum Commitments
Remainder of 2018		13,977
2,019		38,641
2,020		16,365
2,021		175
2,022		131
Thereafter		241
Total		$ 69,530
EVOC
Service Fee Commitment [Line Items]
Amount of fixed annual services fee payments	$ 23,600
Term of Services Agreement	5 years
Period after which Services Agreement is subject to termination by either party	2 years

Subsequent Events (Details)

Subsequent Events (Details) - Affiliate - Karnes County Contribution Agreement - Tranche III - Subsequent Event shares in Millions	Oct. 04, 2018shares
Class A
Subsequent Event [Line Items]
Issuance of earnout share consideration (in shares)	1.1
Class B
Subsequent Event [Line Items]
Issuance of earnout share consideration (in shares)	2.9