Magnolia Oil & Gas (MGY) 10-Q 5 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Nov. 04, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-38083
Entity Registrant Name	Magnolia Oil & Gas Corp
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-5365682
Entity Address, Address Line One	Nine Greenway Plaza, Suite 1300
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77046
City Area Code	713
Local Phone Number	842-9050
Title of 12(b) Security	Class A Common Stock, par value $0.0001
Trading Symbol	MGY
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001698990
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		167,280,858
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		91,789,814

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
CURRENT ASSETS
Cash and cash equivalents	$ 164,489	$ 135,758
Accounts receivable	120,664	140,284
Drilling advances	2,055	12,259
Other current assets	5,047	4,058
Total current assets	292,255	292,359
PROPERTY, PLANT AND EQUIPMENT
Oil and natural gas properties	3,741,357	3,250,742
Other	2,710	360
Accumulated depreciation, depletion and amortization	(563,901)	(177,898)
Total property, plant and equipment, net	3,180,166	3,073,204
OTHER ASSETS
Deferred financing costs, net	8,980	10,731
Equity method investment	19,482	18,873
Intangible assets, net	27,477	38,356
Other long-term assets	4,773	0
TOTAL ASSETS	3,533,133	3,433,523
CURRENT LIABILITIES
Accounts payable and accrued liabilities	186,627	196,357
Other current liabilities	3,684	1,004
Total current liabilities	190,311	197,361
LONG-TERM LIABILITIES
Long-term debt, net	389,528	388,635
Asset retirement obligations, net of current	93,102	84,979
Deferred taxes, net	74,200	54,593
Other long-term liabilities	2,039	0
Total long-term liabilities	558,869	528,207
COMMITMENTS AND CONTINGENCIES (Note 16)
Additional paid-in capital	1,704,652	1,641,237
Treasury Stock, at cost, 950 shares in 2019	(9,722)	0
Retained earnings	74,823	35,507
Noncontrolling interest	1,014,174	1,031,186
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	3,533,133	3,433,523
Class A Common Stock, $0.0001 par value, 1,300,000 shares authorized, 168,260 shares issued and 167,310 shares outstanding in 2019 and 156,333 shares issued and outstanding in 2018
Common stock	17	16
Class B Common Stock, $0.0001 par value, 225,000 shares authorized, 91,790 and 93,346 shares issued and outstanding in 2019 and 2018, respectively
Common stock	$ 9	$ 9

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical)	Sep. 30, 2019$ / sharesshares
Treasury stock (in shares)	950,000
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Common stock, shares authorized (in shares)	1,300,000,000
Common stock, shares issued (in shares)	168,260,000
Common stock, shares outstanding (in shares)	167,310,000
Class B Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Common stock, shares authorized (in shares)	225,000,000
Common stock, shares issued (in shares)	91,790,000
Common stock, shares outstanding (in shares)	91,790,000

Consolidated and Combined State

Consolidated and Combined 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, 2019	Jul. 30, 2018	Sep. 30, 2019
REVENUES
Total revenues	$ 76,887	$ 178,163	$ 244,799	$ 449,186	$ 706,432
OPERATING EXPENSES
Lease operating expenses	3,681	11,016	24,344	23,513	70,755
Gathering, transportation and processing	2,240	5,353	9,270	12,929	26,016
Taxes other than income	2,087	9,351	13,333	23,763	40,825
Exploration expense	40	11,221	3,924	492	10,017
Asset retirement obligation accretion	21	391	1,394	104	4,095
Depreciation, depletion and amortization	23,157	65,902	143,894	137,871	385,942
Amortization of intangible assets	0	2,418	3,626	0	10,879
General and administrative expenses	1,701	10,297	17,345	12,710	52,648
Transaction related costs	0	22,366	0	0	438
Total operating costs and expenses	32,927	138,315	217,130	211,382	601,615
OPERATING INCOME	43,960	39,848	27,669	237,804	104,817
OTHER INCOME (EXPENSE)
Income (loss) from equity method investee	(345)	309	92	711	608
Interest expense, net	0	(4,959)	(6,896)	0	(21,611)
Gain (loss) on derivatives, net	3,865	0	0	(18,127)	0
Other income (expense), net	24	(7,019)	21	(50)	8
Total other income (expense)	3,544	(11,669)	(6,783)	(17,466)	(20,995)
INCOME BEFORE INCOME TAXES	47,504	28,179	20,886	220,338	83,822
Income tax expense	766	3,538	3,529	1,785	12,449
NET INCOME	46,738	24,641	17,357	218,553	71,373
LESS: Net income attributable to noncontrolling interest	0	18,465	6,810	0	29,294
NET INCOME ATTRIBUTABLE TO MAGNOLIA	46,738	6,176	10,547	218,553	42,079
LESS: Non-cash deemed dividend related to warrant exchange	0	0	2,763	0	2,763
NET INCOME ATTRIBUTABLE TO CLASS A COMMON STOCK	46,738	$ 6,176	$ 7,784	218,553	$ 39,316
NET INCOME PER COMMON SHARE
Basic (in dollars per share)		$ 0.04	$ 0.05		$ 0.25
Diluted (in dollars per share)		$ 0.04	$ 0.05		$ 0.24
WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
Basic (in shares)		151,992	166,872		160,051
Diluted (in shares)		157,072	167,108		161,488
Oil revenues
REVENUES
Total revenues	68,487	$ 143,202	$ 207,840	399,124	$ 584,009
Natural gas revenues
REVENUES
Total revenues	3,646	13,414	21,243	22,135	71,208
Natural gas liquids revenues
REVENUES
Total revenues	$ 4,754	$ 21,547	$ 15,716	$ 27,927	$ 51,215

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	Treasury Stock	Retained Earnings	Noncontrolling Interest
Balance at beginning of period at Dec. 31, 2017	$ 1,597,838
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Parents’ contribution, net	133,117
Net income	85,366
Balance at end of period at Mar. 31, 2018	1,816,321
Balance at beginning of period at Dec. 31, 2017	1,597,838
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	218,553
Balance at end of period 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
Balance at beginning of period at Mar. 31, 2018	1,816,321
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Parents’ distributions, net	(48,937)
Net income	86,449
Balance at end of period at Jun. 30, 2018	1,853,833
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Parents’ distributions, net	(21,539)
Net income	46,738
Balance at end of period 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]
Shares 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
Common stock issued in private placement (in shares)					35,500
Common stock issued 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 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	24,641
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	2,642,167			1,650,518	$ 16			$ 9			$ 0	1,647,905		2,588	991,649
Balance at beginning of period 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
Balance at end of period (in shares) at Dec. 31, 2018					156,333			93,346					0
Balance at end of period at Dec. 31, 2018	2,707,955			1,676,769	$ 16			$ 9				1,641,237	$ 0	35,507	1,031,186
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
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	24,641			6,176										6,176	18,465
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 (in shares) at Sep. 30, 2018					155,228			90,451			0
Balance at end of period at Sep. 30, 2018	2,642,167			1,650,518	$ 16			$ 9			$ 0	1,647,905		2,588	991,649
Balance at beginning of period (in shares) at Dec. 31, 2018					156,333			93,346					0
Balance at beginning of period at Dec. 31, 2018	2,707,955			1,676,769	$ 16			$ 9				1,641,237	$ 0	35,507	1,031,186
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	2,432			2,432								2,432
Final settlement adjustment related to Business Combination (in shares)					(496)			(1,556)
Final settlement adjustment related to Business Combination	(25,245)			(6,095)								(6,095)			(19,150)
Contributions from noncontrolling interest owners	8,809														8,809
Net income	22,713			13,026										13,026	9,687
Changes in ownership interest adjustment	(87)			(919)								(919)			832
Balance at end of period (in shares) at Mar. 31, 2019					155,837			91,790					0
Balance at end of period at Mar. 31, 2019	2,716,577			1,685,213	$ 16			$ 9				1,636,655	$ 0	48,533	1,031,364
Balance at beginning of period (in shares) at Dec. 31, 2018					156,333			93,346					0
Balance at beginning of period at Dec. 31, 2018	2,707,955			1,676,769	$ 16			$ 9				1,641,237	$ 0	35,507	1,031,186
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	71,373
Balance at end of period (in shares) at Sep. 30, 2019					168,260			91,790					950
Balance at end of period at Sep. 30, 2019	2,783,953			1,769,779	$ 17			$ 9				1,704,652	$ (9,722)	74,823	1,014,174
Balance at beginning of period (in shares) at Mar. 31, 2019					155,837			91,790					0
Balance at beginning of period at Mar. 31, 2019	2,716,577			1,685,213	$ 16			$ 9				1,636,655	$ 0	48,533	1,031,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued as part of the Business Combination (in shares)					3,055
Common stock issued as part of the Business Combination	33,693			33,693								33,693
Stock based compensation expense	3,115			3,115								3,115
Offering expenses incurred in connection with warrants exchange	(1,055)			(1,055)								(1,055)
Distributions to noncontrolling interest owners	(227)														(227)
Net income	31,303			18,506										18,506	12,797
Changes in ownership interest adjustment	742			108								108			634
Balance at end of period (in shares) at Jun. 30, 2019					158,892			91,790					0
Balance at end of period at Jun. 30, 2019	2,784,148			1,739,580	$ 16			$ 9				1,672,516	$ 0	67,039	1,044,568
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	2,829			2,829								2,829
Common stock issued in connection with warrants exchange (in shares)					9,179
Common stock issued in connection with warrants exchange	(1,138)			(1,138)	$ 1							1,624		(2,763)
Common stock issued related to stock based compensation, net (in shares)					189
Common stock issued related to stock based compensation, net	(532)			(532)								(532)
Common stock repurchased (in shares)													950
Common stock repurchased	(9,722)			(9,722)									$ (9,722)
Distributions to noncontrolling interest owners	(489)														(489)
Net income	17,357			10,547										10,547	6,810
Changes in ownership interest adjustment	(8,500)			28,215								28,215			(36,715)
Balance at end of period (in shares) at Sep. 30, 2019					168,260			91,790					950
Balance at end of period at Sep. 30, 2019	$ 2,783,953			$ 1,769,779	$ 17			$ 9				$ 1,704,652	$ (9,722)	$ 74,823	$ 1,014,174

Consolidated and Combined Sta_2

Consolidated and Combined 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, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 24,641	$ 218,553	$ 71,373
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	65,902	137,871	385,942
Amortization of intangible assets	2,418	0	10,879
Exploration expense, non-cash	0	0	536
Asset retirement obligations accretion expense	391	104	4,095
Amortization of deferred financing costs	570	0	2,644
Loss on derivatives, net	0	18,127	0
Cash settlements of matured derivative contracts	0	(27,617)	0
Deferred taxes	3,493	324	11,765
Contingent consideration change in fair value	6,700	0	0
Stock based compensation	0	0	8,376
Other	(218)	(796)	(526)
Changes in operating assets and liabilities:
Accounts receivable	(77,500)	(61,405)	(6,937)
Prepaid expenses and other assets	(275)	0	996
Accounts payable and accrued liabilities	64,511	36	(6,345)
Drilling advances	(3,376)	0	10,205
Other assets and liabilities, net	45	(385)	(4,392)
Net cash provided by operating activities	87,302	284,812	488,611
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds withdrawn from Trust Account	656,078	0	0
Acquisition of EnerVest properties	(1,219,217)	0	4,250
Acquisitions, other	(135,652)	(150,139)	(93,221)
Additions to oil and natural gas properties	(33,724)	(197,314)	(364,859)
Payment of Contingent Consideration	(26,000)	0	0
Other investing	0	0	(247)
Net cash used in investing activities	(758,515)	(347,453)	(454,077)
CASH FLOW FROM FINANCING ACTIVITIES
Parents’ contribution, net	0	62,641	0
Contributions from noncontrolling interest owners	0	0	7,301
Distributions to noncontrolling interest owners	0	0	(716)
Issuance of common stock	355,000	0	0
Proceeds from issuance of long term debt	400,000	0	0
Repayments of deferred underwriting compensation	(22,750)	0	0
Cash paid for debt issuance costs	(23,336)	0	0
Common stock repurchased	0	0	(9,722)
Other financing activities	(1,009)	0	(2,666)
Net cash provided by (used in) financing activities	707,905	62,641	(5,803)
NET CHANGE IN CASH AND CASH EQUIVALENTS	36,692	0	28,731
Cash and cash equivalents – Beginning of period	23	0	135,758
Cash and cash equivalents – End of period	$ 36,715	$ 0	$ 164,489

Description of Business and Bas

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
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 (formerly TPG Pace Energy Holdings Corp.) (the “Company” or “Magnolia”) was incorporated in Delaware on February 14, 2017. On March 15, 2018, the Company formed three 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 of which are Delaware limited liability companies formed in contemplation of the Business Combination (as defined herein). Business Combination On July 31, 2018 (the “Closing Date”), the Company and Magnolia LLC consummated the acquisition of the following: • 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 • a 35% membership interest (the “Ironwood Interests”) 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 (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 an 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 Senior 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. The Company’s oil and natural gas properties are located primarily in Karnes County and the Giddings Field in South Texas, where the Company targets the Eagle Ford Shale and Austin Chalk formations. 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 In accordance with accounting principles generally accepted in the United States of America (“GAAP”), the Company was the acquirer in the Business Combination and the Karnes County Business, the Giddings Assets, and the Ironwood Interests were 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. Although the Karnes County Contributors are not under common control, each were managed by the same managing general partner, EnerVest, and as such, these Predecessor financial statements have been presented on a combined basis for financial reporting purposes. For the periods on or after the Business Combination, the Company, including the combination 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 “Predecessor Period”) and the period after the Business Combination, which includes the period from July 31, 2018 to September 30, 2018 (the “2018 Successor Period”), and the three and nine months ended September 30, 2019 (the “2019 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 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 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. In addition, Parents’ Net Investment represents the Karnes County Contributors’ interest in the recorded net assets of the Karnes County Business and represents the cumulative net investment of the Karnes County Contributors’ in the Karnes County Business through the dates presented, inclusive of cumulative operating results. The Karnes County Contributors utilized EnerVest’s centralized processes and systems for its treasury services and the Karnes County Business’ cash activity was commingled with other oil and gas assets that were not part of the Business Combination. As such, the net results of the cash transactions between the Karnes County Business and the Karnes County Contributors are reflected as Parents’ contributions and distributions in the accompanying Combined Statement of Changes in Parents’ Net Investment. The Predecessor financial statements also include a portion of indirect costs for salaries and benefits, rent, accounting, legal services, and other expenses. In addition to the allocation of indirect costs, the financial statements reflect certain agreements executed by the Karnes County Contributors for the benefit of the Karnes County Business, including price risk management instruments. The allocations methodologies for significant allocated items include: Corporate G&A - 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, which were used, in part, to acquire the Karnes County Business as well as other oil and natural properties that were not part of the Business Combination. As such, the management fee was allocated to the Karnes County Business using a ratio of asset acquisitions value to total asset acquisitions completed by the Karnes County Contributors, for the Predecessor Period. Derivatives - Certain Karnes County Contributors entered into financial instruments to manage the Karnes County Business’ exposure to changes in commodity prices for the Karnes County Business as well as other oil and natural gas properties that were not part of the Business Combination, on a combined basis. The commodity derivative activity was allocated to the Karnes County Business using a ratio of expected crude oil and condensate, natural gas liquids (“NGLs”), and natural gas volumes produced, on an equivalents basis, by the Karnes County Business to the Karnes County Contributors’ total expected crude oil and condensate, NGLs, and natural gas produced, on an equivalents basis, for the Predecessor Period. Indebtedness - The Karnes County Business did not historically have outstanding indebtedness, but its oil and natural gas properties were collateral to various credit facilities held by the Karnes County Contributors and/or EnerVest. Amounts outstanding on these credit facilities have not been allocated to the Karnes County Business as they were not directly attributable to the Karnes County Business. Management believes the allocation methodologies used are reasonable and result in an allocation of the indirect costs and other items to operate the Karnes County Business as if it were a stand-alone entity. These allocations, however, may not be indicative of the cost of future operations or the amount of future allocations. Direct costs were included at the historical amounts related to each reported period. The accompanying unaudited interim consolidated and combined financial statements have been prepared in accordance with 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 GAAP have been omitted. Certain amounts have been reclassified to conform to the current period presentation resulting from the adoption of ASU No. 2014-09, Revenue from Contracts with Customers. See Note 3 - Revenue Recognition for additional information. 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 Annual Report on Form 10-K for the fiscal year ended December 31, 2018.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies As of September 30, 2019 , the Company’s significant accounting policies are consistent with those discussed in Note 2 - Summary of Significant Accounting Policies of its consolidated financial statements contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018, with the exception of Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” and as noted below. Leases In February 2016, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2016-02, Leases, which requires 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. 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 Company elected the package of transition practical expedients provided by the new standard that allow the Company to not reassess under the new standard its prior conclusions about lease identification, classification related to contracts that commenced prior to adoption, and to apply the standard prospectively to all new or modified land easements and rights-of-way. The Company has also elected a policy to not recognize right of use assets and lease liabilities related to short-term leases. The Company has lease agreements with lease and non-lease components, which are generally accounted for as a single lease component. Magnolia adopted this standard on January 1, 2019 and recognized right of use assets and lease liabilities for certain commitments primarily related to real estate, vehicles, and field equipment, while prior reporting periods are presented in accordance with historical accounting treatment under ASC Topic 840, Leases (“ASC 840”). The Company determines if an arrangement is a lease at inception. Operating leases are included in other long-term assets, other current liabilities, and other long-term liabilities in Magnolia’s consolidated balance sheet as of September 30, 2019 . Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Magnolia’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expenses for lease payments are recognized on a straight-line basis over the lease term. For more information, refer to Note 10 - Leases. Recent Accounting Pronouncements In June 2016 the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standards update requires the use of a forward-looking “expected loss” model as opposed to the current “incurred loss” model. This standard is effective for the Company in the first quarter of 2020. The Company is currently evaluating the new standard and does not believe the adoption will have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). The amendments in the update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software and hosting arrangements that include an internal-use software license. The Company early adopted ASU 2018-15 effective April 1, 2019, with prospective application. The adoption did not have a material impact on the Company’s consolidated financial statements.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. This ASU and the associated subsequent amendments (collectively, “ASC 606”), superseded virtually all of the revenue recognition guidance in GAAP by requiring companies to recognize revenue using a five-step model. 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. Magnolia adopted this standard on December 31, 2018 for all Successor Periods using a modified retrospective approach. There were no significant changes to the timing of revenue recognized for sales of production as a result of ASC 606. However, the new guidance resulted in certain changes to the classification of processing and other fees between revenue and gathering, transportation, and processing expense. The change also resulted in an increase to the production volumes and depreciation, depletion and amortization. The amounts included in the accompanying unaudited interim consolidated financial statements for the 2018 Successor Period were reclassified in order to conform to the current period presentation resulting from the adoption of ASC 606 and are considered immaterial. The Predecessor Period has not been restated and continues to be reported under the accounting standards in effect for that period. Oil, Natural Gas, and NGL Revenues Magnolia’s revenues include the sale of crude oil, natural gas, and NGLs. Oil, natural gas, and NGL sales are recognized as revenue when production is sold to a customer in fulfillment of performance obligations under the terms of agreed contracts. Performance obligations primarily comprise delivery of oil, natural gas, or NGLs at a delivery point, as negotiated within each contract. Each barrel of oil, million Btu of natural gas, gallon of NGLs, or other unit of measure is separately identifiable and represents a distinct performance obligation to which the transaction price is allocated. The Company’s oil production is primarily sold under market-sensitive contracts that are typically priced at a differential to the New York Mercantile Exchange (“NYMEX”) price or at purchaser posted prices for the producing area. For oil contracts, the Company generally records sales based on the net amount received. For natural gas contracts, the Company generally records wet gas sales (which consists of natural gas and NGLs based on end products after processing) at the wellhead or inlet of the gas processing plant (i.e., the point of control transfer) as revenues net of gathering, transportation, and processing expenses if the processor is the customer and there is no redelivery of commodities to the Company at the tailgate of the plant. Conversely, the Company generally records residual natural gas and NGL sales at the tailgate of the plant (i.e., the point of control transfer) on a gross basis along with the associated gathering, transportation, and processing expenses if the processor is a service provider and there is redelivery of one or several commodities to the Company at the tailgate of the plant. The facts and circumstances of an arrangement are considered and judgment is often required in making this determination. For processing contracts that require noncash consideration in exchange for processing services, the Company recognizes revenue and an equal gathering, transportation, and processing expense for commodities transferred to the service provider. Contract Balances Customers are invoiced once the Company’s performance obligations have been satisfied. Payment terms and conditions vary by contract type, although terms generally include a requirement of payment within 30 days . There are no judgments that significantly affect the amount or timing of revenue from contracts with customers. Accordingly, the Company’s product sales contracts do not give rise to material contract assets or contract liabilities. The Company’s receivables consist mainly of receivables from oil and natural gas purchasers and from joint interest owners on properties the Company operates. Receivables from contracts with customers totaled $113.2 million as of September 30, 2019 and $100.1 million as of December 31, 2018. Accounts receivable are stated at the historical carrying amount net of write-offs and allowance for doubtful accounts. 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, 2019 or December 31, 2018. Disaggregation of Revenue The Company has concluded that disaggregating revenue by product type appropriately depicts how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors and has reflected this disaggregation of revenue on the Company’s consolidated and combined statements of operations for all periods presented. Performance Obligations Performance obligations are satisfied at a point in time once control of the product has been transferred to the customer. The Company considers a variety of facts and circumstances in assessing the point of control transfer, including but not limited to: whether the purchaser can direct the use of the hydrocarbons, the transfer of significant risks and rewards, the Company’s right to payment, and transfer of legal title. The Company does not disclose the value of unsatisfied performance obligations for contracts as all contracts have either an original expected length of one year or less, or the entire future consideration is variable and allocated entirely to a wholly unsatisfied performance obligation.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	Acquisitions Acquisitions (Successor) 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, subject to certain conditions; 31.8 million shares of Class A Common Stock; and approximately $911.5 million in cash. The Giddings Sellers received approximately $282.7 million in cash. The Ironwood Sellers received $25.0 million in cash in exchange for the Ironwood Interests. On March 29, 2019, Magnolia and EnerVest consummated the final settlement pursuant to the Contribution and Merger Agreement and as otherwise agreed to by the parties, with Magnolia receiving a net cash payment of $4.3 million and the Karnes County Contributors forfeiting to Magnolia 0.5 million shares of Class A Common Stock and 1.6 million shares of Class B Common Stock (and forfeiting a corresponding number of Magnolia LLC Units to Magnolia LLC). The Business Combination has been accounted for using the acquisition method. The acquisition method of accounting is based on ASC 805 “Business Combinations,” 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 were entitled to receive an aggregate of up to 13.0 million additional shares of Class A Common Stock or shares of Class B Common Stock (and a corresponding number of Magnolia LLC Units) based on certain EBITDA and free cash flow or stock price thresholds. As of December 31, 2018, the Company had met the defined stock price thresholds and, as a result, the Company had issued an aggregate of 3.6 million additional shares of Class A Common Stock and 9.4 million additional shares of Class B Common Stock (and a corresponding number of Magnolia LLC Units) 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. The purchase consideration for the Business Combination was as follows: (In thousands) Purchase Consideration: Cash consideration $ 1,214,966 Stock consideration (1) 1,398,238 Fair value of contingent earnout purchase consideration (2) 169,000 Total purchase price consideration $ 2,782,204 (1) At closing of the Business Combination, the Karnes County Contributors received 83.9 million shares of Class B Common Stock (and a corresponding number of Magnolia LLC Units) and 31.8 million shares of Class A Common Stock. On March 29, 2019, Magnolia and EnerVest consummated the final settlement pursuant to the Contribution and Merger Agreement as agreed to by the parties, with the Karnes County Contributors forfeiting an aggregate of 2.1 million shares of Class A and Class B Common Stock to Magnolia (and a corresponding number of Magnolia LLC Units). (2) Pursuant to ASC 805, ASC 480, “Distinguishing Liabilities from Equity,” and ASC 815, “Derivatives and Hedging,” the Karnes County earnout consideration was valued at fair value as of the Closing Date and was classified in stockholders’ equity. The Giddings earnout was valued at fair value as of the Closing Date and was 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 acquired and liabilities assumed on the acquisition date: (In thousands) Fair value of assets acquired Accounts receivable $ 61,790 Other current assets 2,853 Oil and natural gas properties (1) 2,813,140 Ironwood equity investment 18,100 Total fair value of assets acquired 2,895,883 Fair value of liabilities assumed Accounts payable and other current liabilities (65,908 ) Asset retirement obligations (34,132 ) Deferred tax liability (13,639 ) Fair value of net assets acquired $ 2,782,204 (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. The Company incurred $24.8 million in transaction costs associated with the Business Combination. 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. 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) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Total revenues $ 267,659 $ 723,768 Net income attributable to Class A Common Stock 57,891 151,316 Net income per share - basic 0.39 1.02 Net income per share - diluted 0.38 0.98 Non-Compete On the Closing Date, the Company and EnerVest, separate and apart from the Business Combination, entered into a non-compete agreement (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 4.0 million shares of Class A Common Stock issuable in two tranches of 2.0 million shares in two and one half and four years from the Closing Date provided EnerVest does not compete with Magnolia in the Eagle Ford Shale until the later of July 31, 2022 or the date the Services Agreement with EnerVest Operating, LLC (“EVOC”), a wholly owned subsidiary of EnerVest, (the “Services Agreement”), is terminated. For more discussion on the Non-Compete, refer to Note 7 - Intangible Assets . Harvest Acquisition On August 31, 2018, the Company completed the acquisition of substantially all of Harvest Oil & Gas Corporation’s South Texas assets for approximately $133.3 million in cash and 4.2 million shares of 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. On March 14, 2019, Magnolia consummated the final settlement with Harvest receiving a cash payment of $1.4 million . The transaction was accounted for as a business combination. The following table summarizes the allocation of the purchase consideration to the assets acquired and liabilities assumed: (In thousands) Fair value of assets acquired Other current assets $ 1,290 Oil and natural gas properties (1) 201,337 Total fair value of assets acquired 202,627 Fair value of liabilities assumed Asset retirement obligations and other current liabilities (9,666 ) Fair value of net assets acquired $ 192,961 (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. Certain Other Acquisitions • On May 31, 2019, the Company completed the acquisition of certain oil and gas assets located in the Company’s Karnes County Assets for approximately $36.3 million in cash, subject to customary closing adjustments, and approximately 3.1 million shares of the Company’s Class A Common Stock. The transaction was accounted for as an asset acquisition. • On February 5, 2019, Magnolia Operating formed a joint venture, Highlander Oil & Gas Holdings LLC (“Highlander”), to complete the acquisition of a 72% working interest in the Eocene-Tuscaloosa Zone, Ultra Deep Structure gas well located in St. Martin Parish, Louisiana and 31.1 million royalty trust units in the Gulf Coast Ultra Deep Royalty Trust from McMoRan Oil & Gas, LLC. Highlander paid cash consideration of $50.9 million , for such interests. MGY Louisiana LLC, a wholly owned subsidiary of Magnolia Operating, holds approximately 85% of the units in Highlander. The transaction was accounted for as an asset acquisition. Acquisitions (Predecessor) Subsequent 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) 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

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities (Predecessor)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities (Predecessor)	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 NGLs. As such, future earnings are subject to fluctuation due to changes in the market price of oil, natural gas, and NGLs. The Company has not engaged 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 the risk of volatility in the prices of oil, natural gas, and NGLs and their 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 were recorded immediately to earnings as “Gain (loss) on derivatives, net” in the combined statements of operations. During the periods from July 1 through July 30, 2018 and January 1 through July 30, 2018, the Predecessor incurred a gain on derivatives of $3.9 million and a loss on derivatives of $18.1 million

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
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 under ASC 820. 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. Fair Values - Recurring (Predecessor) The Predecessor’s derivatives consisted of over-the-counter contracts that were not traded on a public exchange. As the fair value of these derivatives was based on inputs using market prices obtained from independent brokers or determined using quantitative models that used 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 were determined at discrete points in time based on relevant market data. Furthermore, fair values were adjusted to reflect the credit risk inherent in the transaction, which may have included amounts to reflect counterparty credit quality and/or the effect of the Predecessor’s creditworthiness. 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 4 - Acquisitions for additional information. Deemed Dividend In July 2019, the Company issued an aggregate of 9.2 million shares of Class A Common Stock in exchange for all of its warrants. The difference in fair value between the Class A Common Stock issued and the warrants exchanged was recorded as a non-cash deemed dividend for the incremental value provided to the holders of the warrants. The fair value of the non-cash deemed dividend related to the warrant exchange was determined based on unadjusted quoted prices in an active market, which are considered a Level 1 input in the fair value hierarchy. Refer to Note 11 - Stockholders’ Equity for additional information. Debt Obligations The carrying value and fair value of the financial instrument that is not carried at fair value in the accompanying consolidated balance sheet as of September 30, 2019 is as follows: September 30, 2019 (In thousands) Carrying Value Fair Value Long-term debt $ 389,528 $ 404,000 The fair value of the 2026 Senior Notes at September 30, 2019 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 combinations and asset retirement obligations.

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets Non-Compete Agreement On the Closing Date, the Company and EnerVest, separate and apart from the Business Combination, 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”) until the later of July 31, 2022 or the date the Services Agreement is terminated. Under the Non-Compete, an affiliate of EnerVest will have the right to receive 4.0 million shares of Class A Common Stock in two tranches of 2.0 million shares in two and one half and four years from the Closing Date provided EnerVest does not compete in the Market Area. The Company recorded an estimated cost of $44.4 million for the Non-Compete as intangible assets on the Company’s consolidated balance sheet. These intangible assets have a definite life and are subject to amortization utilizing the straight-line method over their economic life, currently estimated to be two and one half to four years . The Company includes the amortization in “Amortization of intangible assets” on the Company’s consolidated statement of operations. (In thousands) September 30, 2019 Non-compete intangible assets $ 44,400 Accumulated amortization (16,923 ) Intangible assets, net $ 27,477 Weighted average amortization period (in years) 3.25

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
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 and its subsidiaries operate. 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 period in which they occur. Income tax expense recorded for the period is based on applying an estimated annual effective income tax rate to the net income from January 1, 2019 through September 30, 2019. There were no significant unusual or infrequently occurring items that are required to be recorded as discrete items as of September 30, 2019 . 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 Company’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 expense may change as new events occur, more experience is obtained, additional information becomes known, or as the tax environment changes. For the three and nine months ended September 30, 2019 , the Company incurred U.S. federal income tax expense of approximately $3.1 million and $11.6 million , respectively. The Company’s annual effective tax rate for the three and nine months ended September 30, 2019 was 16.9% and 14.9% , respectively. The primary differences between the annual effective tax rate and the statutory rate of 21.0% are income attributable to noncontrolling interest and state taxes. The Company’s income tax provision consists of the following components: Successor Predecessor (In thousands) Three Months Ended Nine Months Ended July 31, 2018 July 1, 2018 January 1, 2018 Through Current: Federal $ — $ — $ — $ — $ — State 115 684 45 631 1,461 115 684 45 631 1,461 Deferred: Federal 3,135 11,588 3,493 — — State 279 177 — 135 324 3,414 11,765 3,493 135 324 Total provision $ 3,529 $ 12,449 $ 3,538 $ 766 $ 1,785 The Company is subject to U.S. federal income tax, the margin tax in the state of Texas, and Louisiana corporate income tax. No amounts have been accrued for income tax uncertainties or interest and penalties as of September 30, 2019 . 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’s tax years since its formation remain subject to possible income tax examinations by its major taxing authorities for all periods.

Long Term Debt

Long Term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long Term Debt	Long Term Debt The Company’s debt is comprised of the following: (In thousands) September 30, 2019 Revolving credit facility $ — 6.0% Senior Notes due 2026 400,000 Total long-term debt 400,000 Less: Unamortized deferred financing cost (10,472 ) Total debt, net $ 389,528 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 its holding company, 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, 2019 was $550.0 million . The RBL Facility is guaranteed by certain parent companies and subsidiaries of Magnolia LLC and is collateralized by certain of Magnolia Operating’s 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 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 less than 4.00 to 1.00 and, if the leverage ratio is in excess of 3.00 to 1.00, a current ratio of greater than 1.00 to 1.00. As of September 30, 2019 , the Company was in compliance with all covenants under the RBL Facility. Deferred financing costs incurred in connection with securing the RBL Facility were $11.7 million , which are amortized on a straight-line basis over a period of five years and included in “Interest expense, net” in the Company’s consolidated statement of operations. During the three and nine months ended September 30, 2019 , the Company recognized interest expense of $1.1 million and $3.4 million , respectively, 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, 2019 . The Company did no t have any outstanding borrowings under its RBL Facility as of September 30, 2019 . 2026 Senior Notes On the Closing Date, the Issuers issued and sold $ 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 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 and bear interest at the rate of 6.0% per annum. 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 2026 Senior Notes redeemed, plus a “make whole” premium on accrued and unpaid interest, if any, to, but excluding, the date of redemption. After August 1, 2021, the Issuers may redeem all or a part of the Notes based on principal plus a set premium, as set forth in the Indenture, including any accrued and unpaid interest. The Company incurred $11.8 million of deferred financing costs related to the issuance of the 2026 Senior Notes, which were capitalized, are amortized using the effective interest method over the term of the 2026 Senior Notes, and are included in “Interest expense, net” 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, 2019 . During the three and nine months ended September 30, 2019 , the Company recognized interest expense of $6.3 million and $18.9 million , respectively, related to the 2026 Senior Notes. Affiliate Guarantors Certain subsidiaries of the Company 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. 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.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases Magnolia’s leases primarily consist of real estate, vehicles, and field equipment. The Company’s leases have remaining lease terms of up to 8 years , some of which include options to renew or terminate the lease. The exercise of lease renewal options is at the Company’s sole discretion. Magnolia’s lease agreements do not contain any residual value guarantees or restrictive covenants. As most of Magnolia’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The Company used the incremental borrowing rate on January 1, 2019, for operating leases that commenced prior to that date. (In thousands) September 30, 2019 Operating Leases Operating lease assets $ 4,772 Operating lease liabilities - current $ 2,724 Operating lease liabilities - long-term 2,039 Total operating lease liabilities $ 4,763 Weighted average remaining lease term (in years) 2.0 Weighted average discount rate 3.8 % For the three and nine months ended September 30, 2019 , respectively, the Company incurred $0.9 million and $2.1 million of lease costs for operating leases included on the Company’s balance sheet, $5.9 million and $21.1 million for short-term lease costs and $0.6 million and $2.5 million for variable lease costs. Cash paid for amounts included in the measurement of lease liabilities in operating cash flows from operating leases for the nine months ended September 30, 2019 is $2.0 million . Maturities of lease liabilities as of September 30, 2019 under the scope of ASC 842 are as follows: (In thousands) Maturity of Lease Liabilities (1) Operating Leases 2019 (remaining) $ 771 2020 2,653 2021 1,170 2022 165 2023 98 After 2023 91 Total lease payments $ 4,948 Less: Interest (185 ) Present value of lease liabilities $ 4,763 (1) As of December 31, 2018, minimum future contractual payments for long-term operating leases under the scope of ASC 840 were $881 thousand in 2019, $646 thousand in 2020, $198 thousand in 2021, $14 thousand in 2022, $15 thousand in 2023 and $63 thousand thereafter.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity 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, 2019 , there were 168.3 million shares issued and 167.3 million shares outstanding of Class A Common Stock. 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, subject to voting obligations under the Stockholder Agreement (defined below). 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 holders of the Class A Common Stock have no preemptive or other subscription rights, and there are no sinking fund provisions applicable to such shares. 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, 2019 , there were 91.8 million shares of Class B Common Stock issued and outstanding. Holders of Class B Common Stock 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 of 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 holders of the Class B Common Stock have no preemptive or other subscription rights, and there are no sinking fund provisions applicable to such shares. Warrants On June 7, 2019, the Company commenced an exchange offer (the “Offer”) and consent solicitation (the “Consent Solicitation”), pursuant to which the Company (1) offered to holders of its warrants the opportunity to receive 0.29 shares of Class A Common Stock in exchange for each warrant validly tendered and (2) solicited the consent from the holders of its warrants to approve an amendment to the Company’s existing warrant agreement, by and between the Company and Continental Stock Transfer & Trust Company, to amend the agreement to provide the Company with the right to require any holder of the Company’s warrants to exchange their warrants for Class A Common Stock at an exchange ratio of 0.261 shares of Class A Common Stock for each whole warrant (the “Warrant Amendment”). Pursuant to the Offer, certain of the Company’s warrantholders, including directors and executive officers, agreed to tender their warrants and provide the corresponding consent to the Warrants Amendment in the Consent Solicitation by entering into the Tender and Support Agreement (as defined below). The Offer and Consent Solicitation expired on July 5, 2019. In connection with the closing of the Offer on July 10, 2019 and the subsequent exercise of the Company’s right to exchange all remaining warrants on July 25, 2019, the Company issued an aggregate of 9.2 million shares of Class A Common Stock in exchange for all of its 31.7 million warrants outstanding, which consisted of 21.7 million public warrants and 10.0 million private placement warrants. As the fair value of the warrants exchanged in the Offer was less than the fair value of the Class A Common Stock issued, the company recorded a non-cash deemed dividend of $2.8 million for the incremental value provided to the warrant holders. The fair value of warrants and the Class A Common Stock was determined using unadjusted quoted prices in an active market, a Level 1 fair value input. The Company capitalized $2.2 million of expenses related to the Offer within additional paid-in capital. Share Repurchase Program On August 5, 2019, the Company’s Board of Directors authorized a share repurchase program of up to 10 million shares. The program does not require purchases to be made within a particular timeframe. As of September 30, 2019 , the Company had repurchased 950 thousand shares of Class A Common Stock at a weighted average price of $10.23 , for a total cost of approximately $9.7 million . Noncontrolling Interest Noncontrolling interest in Magnolia’s consolidated subsidiaries include amounts attributable 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 and the conversion of Class B Common Stock to Class A Common Stock. As of September 30, 2019 , Magnolia owned approximately 64.6% of the interest in Magnolia LLC and the noncontrolling interest was 35.4% . In the first quarter of 2019, Magnolia Operating formed a joint venture, in which MGY Louisiana LLC, a wholly owned subsidiary of Magnolia Operating, holds approximately 85% of the units, with the remaining 15% attributable to noncontrolling interest.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Supplemental cash flow disclosures are presented below: Successor Predecessor (In thousands) Nine Months Ended July 31, 2018 Through September 30, 2018 January 1, 2018 Through Supplemental non-cash operating activity: Cash paid for income taxes $ 390 $ — $ 336 Cash paid for interest 25,687 350 — Supplemental non-cash investing and financing activity: Accruals or liabilities for capital expenditures $ 37,241 $ 45,242 $ 38,028 Contingent Consideration issued in Business Combination — 149,700 — Non-Compete agreement entered into in Business Combination — 44,400 — Equity issuances in connection with acquisitions 33,693 1,481,695 — Non-cash deemed dividend related to warrant exchange 2,763 — — Supplemental non-cash lease operating activity: Right-of-use assets obtained in exchange for operating lease obligations $ 6,720 — —

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock Based Compensation	Stock Based Compensation On October 8, 2018, the Company’s board of directors adopted the “Magnolia Oil & Gas Corporation Long Term Incentive Plan” (the “Plan”), effective as of July 17, 2018. A total of 11.8 million shares of Class A Common Stock have been authorized for issuance under the Plan. The Company granted employees stock based compensation awards in the form of restricted stock units (“RSUs”) and performance stock units (“PSUs”) to enhance the Company and its affiliates’ ability to attract, retain and motivate persons who make important contributions to the Company and its affiliates by providing these individuals with equity ownership opportunities. Shares issued as a result of awards granted under the Plan are generally new shares of Class A Common Stock. Stock based compensation expense is recognized within general and administrative expense on the consolidated statement of operations and was $2.8 million and $8.4 million for the three and nine months ended September 30, 2019 . The Company has elected to account for forfeitures of awards granted under the Plan as they occur in determining compensation expense. Restricted Stock Units The Company grants service-based RSU awards to employees and non-employee directors, which generally vest ratably over a three -year service period. RSUs represent the right to receive shares of Class A Common Stock at the end of the vesting period equal to the number of RSUs granted. RSUs are subject to restrictions on transfer and are generally subject to a risk of forfeiture if the award recipient is no longer an employee or director of the Company for any reason prior to vesting of the award. Compensation expense for the service-based RSU awards is based upon the grant date market value of the award and such costs are recorded on a straight-line basis over the requisite service period for each separately vesting portion of the award, as if the award was, in-substance, multiple awards. Unrecognized compensation expense related to unvested restricted shares at September 30, 2019 was $12.0 million , which the Company expects to recognize over a weighted average period of 2.1 years. The table below summarizes restricted stock unit activity for the nine months ended September 30, 2019 . Restricted Stock Units Weighted Average Grant Date Fair Value Unvested restricted stock units, beginning of period 807,431 $ 13.97 Granted 585,659 $ 12.33 Vested 237,702 $ 14.58 Forfeited — — Unvested restricted stock units, end of period 1,155,388 $ 13.06 Performance Stock Units During the nine months ended September 30, 2019 , the Company granted PSUs to certain employees, with each PSU representing the contingent right to receive one share of Class A Common Stock. The number of shares of Class A Common Stock issuable upon vesting, however, ranges from zero to 150% of the number of PSUs granted based on the total shareholder return (“TSR”) of the Class A Common Stock relative to the TSR achieved by a specific industry peer group over an approximate three -year performance period, the last day of which is also the vesting date. Unrecognized compensation expense related to unvested PSUs at September 30, 2019 was $7.0 million , which the Company expects to recognize over a weighted average period of 2.1 years. The table below summarizes performance stock award and unit activity for the nine months ended September 30, 2019 . Performance Stock Units Weighted Average Grant Date Fair Value Unvested performance stock units, beginning of period 475,312 $ 14.58 Granted 267,482 $ 13.87 Vested 33,333 $ 14.58 Forfeited — — Unvested performance stock units, end of period 709,461 $ 14.31 The grant date fair value of the PSUs granted during the nine months ended September 30, 2019 was $3.7 million , calculated using a Monte Carlo simulation. The following table summarizes the assumptions used to calculate the grant date fair value of these PSUs. Grant Date Fair Value Assumptions Expected term (in years) 2.85 - 2.67 Expected volatility 33.61% - 31.58% Risk-free interest rate 2.48% - 2.29%

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2019
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 Period as the Predecessor was not previously accounted for as a standalone legal entity and did not have publicly traded securities. (In thousands, except per share data) Three Months Ended September 30, 2019 Nine Months Ended July 31, 2018 Through September 30, 2018 Basic: Net Income attributable to Class A Common Stock $ 7,784 $ 39,316 $ 6,176 Weighted average number of common shares outstanding during the period - basic 166,872 160,051 151,992 Net income per common share - basic $ 0.05 $ 0.25 0.04 Diluted: Net Income attributable to Class A Common Stock $ 7,784 $ 39,316 $ 6,176 Weighted average number of common shares outstanding during the period - basic 166,872 160,051 151,992 Add: Dilutive effect warrants and stock based compensation 236 1,437 5,080 Weighted average number of common shares outstanding during the period - diluted 167,108 161,488 157,072 Net income per common share - diluted $ 0.05 $ 0.24 $ 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. The Company excluded 91.8 million , 92.3 million , and 87.6 million of weighted average shares of Class A Common Stock issuable upon conversion of the Class B Common Stock (and the corresponding Magnolia LLC Units) for the three and nine months ended September 30, 2019 and for the period from July 31, 2018 through September 30, 2018, respectively, as the effect was anti-dilutive. In addition, for the three months ended September 30, 2019 the effect of warrants were excluded because their inclusion would be anti-dilutive.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions As of September 30, 2019 , 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 of which are part of the Karnes County Contributors, 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.” 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 is 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 TPG Pace Energy Sponsor LLC, a Delaware limited liability company (“TPG Pace”), the Karnes County Contributors, and the Company’s four independent directors prior to the Business Combination (collectively, the “Holders”), pursuant to which the Company is 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 held as of July 31, 2018 and that they may have acquired or might acquire thereafter, including upon conversion, exchange, or redemption of any other security therefor. Under the 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. Pursuant to the Registration Rights Agreement, the Company has filed and taken effective two registration statements on Form S-3, each of which registered, among others, the offering by the Holders of the shares of Class A Common Stock included therein. Stockholder Agreement On the Closing Date, the Company, TPG Pace, and the Karnes County Contributors entered into the Stockholder Agreement (the “Stockholder Agreement”), under which the Karnes County Contributors are 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 collectively own 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). The Karnes County Contributors are collectively entitled to appoint one director to each committee of the Board (subject to applicable laws and stock exchange rules). Furthermore, TPG Pace was entitled to certain director nomination rights under the Stockholder Agreement, but those rights ceased following a distribution by TPG Pace of its shares in August 2019. Contingent Consideration Pursuant to the Karnes County Contribution Agreement, for a period of five years following the Closing Date, the Company agreed to issue or cause to be issued to the Karnes County Contributors additional equity in the Company and Magnolia LLC upon satisfaction of certain EBITDA and free cash flow or stock price thresholds in three tranches. As of December 31, 2018, the Company had met the defined stock price thresholds and had issued an aggregate of 3.6 million additional shares of Class A Common Stock and 9.4 million additional shares of Class B Common Stock to the Karnes County Contributors and had caused Magnolia LLC to issue 9.4 million additional Magnolia LLC Units to the Karnes County Contributors. Tender and Support Agreement Pursuant to the Offer, certain of the Company’s warrantholders, including directors and executive officers, agreed to tender their warrants by entering into the tender and support agreement, dated as of June 7, 2019, by and between the Company and such holders (the “Tender and Support Agreement”). See Note 11 - Stockholders’ Equity for more information. Predecessor Transactions 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 were allocated to the Predecessor using a ratio of asset acquisitions value to total asset acquisitions completed by the Karnes County Contributors. The management fees and other costs allocated to the Predecessor and included in "General and administrative expenses" in the combined statements of operations were $1.6 million and $11.6 million for the periods of July 1 through July 30, 2018 and January 1 through July 30, 2018, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
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 and the Company 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. At September 30, 2019 , the Company does not believe the outcome of any such disputes or legal actions will have a material effect on its consolidated statement of operations, balance sheet, or cash flows. 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. Risks and Uncertainties

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation In accordance with accounting principles generally accepted in the United States of America (“GAAP”), the Company was the acquirer in the Business Combination and the Karnes County Business, the Giddings Assets, and the Ironwood Interests were 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. Although the Karnes County Contributors are not under common control, each were managed by the same managing general partner, EnerVest, and as such, these Predecessor financial statements have been presented on a combined basis for financial reporting purposes. For the periods on or after the Business Combination, the Company, including the combination 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 “Predecessor Period”) and the period after the Business Combination, which includes the period from July 31, 2018 to September 30, 2018 (the “2018 Successor Period”), and the three and nine months ended September 30, 2019 (the “2019 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 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 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. In addition, Parents’ Net Investment represents the Karnes County Contributors’ interest in the recorded net assets of the Karnes County Business and represents the cumulative net investment of the Karnes County Contributors’ in the Karnes County Business through the dates presented, inclusive of cumulative operating results. The Karnes County Contributors utilized EnerVest’s centralized processes and systems for its treasury services and the Karnes County Business’ cash activity was commingled with other oil and gas assets that were not part of the Business Combination. As such, the net results of the cash transactions between the Karnes County Business and the Karnes County Contributors are reflected as Parents’ contributions and distributions in the accompanying Combined Statement of Changes in Parents’ Net Investment. The Predecessor financial statements also include a portion of indirect costs for salaries and benefits, rent, accounting, legal services, and other expenses. In addition to the allocation of indirect costs, the financial statements reflect certain agreements executed by the Karnes County Contributors for the benefit of the Karnes County Business, including price risk management instruments. The allocations methodologies for significant allocated items include: Corporate G&A - 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, which were used, in part, to acquire the Karnes County Business as well as other oil and natural properties that were not part of the Business Combination. As such, the management fee was allocated to the Karnes County Business using a ratio of asset acquisitions value to total asset acquisitions completed by the Karnes County Contributors, for the Predecessor Period. Derivatives - Certain Karnes County Contributors entered into financial instruments to manage the Karnes County Business’ exposure to changes in commodity prices for the Karnes County Business as well as other oil and natural gas properties that were not part of the Business Combination, on a combined basis. The commodity derivative activity was allocated to the Karnes County Business using a ratio of expected crude oil and condensate, natural gas liquids (“NGLs”), and natural gas volumes produced, on an equivalents basis, by the Karnes County Business to the Karnes County Contributors’ total expected crude oil and condensate, NGLs, and natural gas produced, on an equivalents basis, for the Predecessor Period. Indebtedness - The Karnes County Business did not historically have outstanding indebtedness, but its oil and natural gas properties were collateral to various credit facilities held by the Karnes County Contributors and/or EnerVest. Amounts outstanding on these credit facilities have not been allocated to the Karnes County Business as they were not directly attributable to the Karnes County Business. Management believes the allocation methodologies used are reasonable and result in an allocation of the indirect costs and other items to operate the Karnes County Business as if it were a stand-alone entity. These allocations, however, may not be indicative of the cost of future operations or the amount of future allocations. Direct costs were included at the historical amounts related to each reported period. The accompanying unaudited interim consolidated and combined financial statements have been prepared in accordance with 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 GAAP have been omitted. Certain amounts have been reclassified to conform to the current period presentation resulting from the adoption of ASU No. 2014-09, Revenue from Contracts with Customers. See Note 3 - Revenue Recognition for additional information. 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 Annual Report on Form 10-K for the fiscal year ended December 31, 2018.
Leases	Leases In February 2016, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2016-02, Leases, which requires 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. 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 Company elected the package of transition practical expedients provided by the new standard that allow the Company to not reassess under the new standard its prior conclusions about lease identification, classification related to contracts that commenced prior to adoption, and to apply the standard prospectively to all new or modified land easements and rights-of-way. The Company has also elected a policy to not recognize right of use assets and lease liabilities related to short-term leases. The Company has lease agreements with lease and non-lease components, which are generally accounted for as a single lease component. Magnolia adopted this standard on January 1, 2019 and recognized right of use assets and lease liabilities for certain commitments primarily related to real estate, vehicles, and field equipment, while prior reporting periods are presented in accordance with historical accounting treatment under ASC Topic 840, Leases (“ASC 840”). The Company determines if an arrangement is a lease at inception. Operating leases are included in other long-term assets, other current liabilities, and other long-term liabilities in Magnolia’s consolidated balance sheet as of September 30, 2019 . Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Magnolia’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expenses for lease payments are recognized on a straight-line basis over the lease term. For more information, refer to
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016 the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standards update requires the use of a forward-looking “expected loss” model as opposed to the current “incurred loss” model. This standard is effective for the Company in the first quarter of 2020. The Company is currently evaluating the new standard and does not believe the adoption will have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). The amendments in the update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software and hosting arrangements that include an internal-use software license. The Company early adopted ASU 2018-15 effective April 1, 2019, with prospective application. The adoption did not have a material impact on the Company’s consolidated financial statements.
Revenue Recognition	Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. This ASU and the associated subsequent amendments (collectively, “ASC 606”), superseded virtually all of the revenue recognition guidance in GAAP by requiring companies to recognize revenue using a five-step model. 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. Magnolia adopted this standard on December 31, 2018 for all Successor Periods using a modified retrospective approach. There were no significant changes to the timing of revenue recognized for sales of production as a result of ASC 606. However, the new guidance resulted in certain changes to the classification of processing and other fees between revenue and gathering, transportation, and processing expense. The change also resulted in an increase to the production volumes and depreciation, depletion and amortization. The amounts included in the accompanying unaudited interim consolidated financial statements for the 2018 Successor Period were reclassified in order to conform to the current period presentation resulting from the adoption of ASC 606 and are considered immaterial. The Predecessor Period has not been restated and continues to be reported under the accounting standards in effect for that period. Oil, Natural Gas, and NGL Revenues Magnolia’s revenues include the sale of crude oil, natural gas, and NGLs. Oil, natural gas, and NGL sales are recognized as revenue when production is sold to a customer in fulfillment of performance obligations under the terms of agreed contracts. Performance obligations primarily comprise delivery of oil, natural gas, or NGLs at a delivery point, as negotiated within each contract. Each barrel of oil, million Btu of natural gas, gallon of NGLs, or other unit of measure is separately identifiable and represents a distinct performance obligation to which the transaction price is allocated. The Company’s oil production is primarily sold under market-sensitive contracts that are typically priced at a differential to the New York Mercantile Exchange (“NYMEX”) price or at purchaser posted prices for the producing area. For oil contracts, the Company generally records sales based on the net amount received. For natural gas contracts, the Company generally records wet gas sales (which consists of natural gas and NGLs based on end products after processing) at the wellhead or inlet of the gas processing plant (i.e., the point of control transfer) as revenues net of gathering, transportation, and processing expenses if the processor is the customer and there is no redelivery of commodities to the Company at the tailgate of the plant. Conversely, the Company generally records residual natural gas and NGL sales at the tailgate of the plant (i.e., the point of control transfer) on a gross basis along with the associated gathering, transportation, and processing expenses if the processor is a service provider and there is redelivery of one or several commodities to the Company at the tailgate of the plant. The facts and circumstances of an arrangement are considered and judgment is often required in making this determination. For processing contracts that require noncash consideration in exchange for processing services, the Company recognizes revenue and an equal gathering, transportation, and processing expense for commodities transferred to the service provider. Contract Balances Customers are invoiced once the Company’s performance obligations have been satisfied. Payment terms and conditions vary by contract type, although terms generally include a requirement of payment within 30 days . There are no judgments that significantly affect the amount or timing of revenue from contracts with customers. Accordingly, the Company’s product sales contracts do not give rise to material contract assets or contract liabilities. The Company’s receivables consist mainly of receivables from oil and natural gas purchasers and from joint interest owners on properties the Company operates. Receivables from contracts with customers totaled $113.2 million as of September 30, 2019 and $100.1 million as of December 31, 2018. Accounts receivable are stated at the historical carrying amount net of write-offs and allowance for doubtful accounts. 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, 2019 or December 31, 2018. Disaggregation of Revenue The Company has concluded that disaggregating revenue by product type appropriately depicts how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors and has reflected this disaggregation of revenue on the Company’s consolidated and combined statements of operations for all periods presented. Performance Obligations Performance obligations are satisfied at a point in time once control of the product has been transferred to the customer. The Company considers a variety of facts and circumstances in assessing the point of control transfer, including but not limited to: whether the purchaser can direct the use of the hydrocarbons, the transfer of significant risks and rewards, the Company’s right to payment, and transfer of legal title. The Company does not disclose the value of unsatisfied performance obligations for contracts as all contracts have either an original expected length of one year or less, or the entire future consideration is variable and allocated entirely to a wholly unsatisfied performance obligation.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Schedule of Purchase Consideration for Business Combination	The purchase consideration for the Business Combination was as follows: (In thousands) Purchase Consideration: Cash consideration $ 1,214,966 Stock consideration (1) 1,398,238 Fair value of contingent earnout purchase consideration (2) 169,000 Total purchase price consideration $ 2,782,204 (1) At closing of the Business Combination, the Karnes County Contributors received 83.9 million shares of Class B Common Stock (and a corresponding number of Magnolia LLC Units) and 31.8 million shares of Class A Common Stock. On March 29, 2019, Magnolia and EnerVest consummated the final settlement pursuant to the Contribution and Merger Agreement as agreed to by the parties, with the Karnes County Contributors forfeiting an aggregate of 2.1 million shares of Class A and Class B Common Stock to Magnolia (and a corresponding number of Magnolia LLC Units). (2) Pursuant to ASC 805, ASC 480, “Distinguishing Liabilities from Equity,” and ASC 815, “Derivatives and Hedging,” the Karnes County earnout consideration was valued at fair value as of the Closing Date and was classified in stockholders’ equity. The Giddings earnout was valued at fair value as of the Closing Date and was 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 Acquired and Liabilities Assumed	The following table summarizes the allocation of the purchase consideration to the assets acquired and liabilities assumed on the acquisition date: (In thousands) Fair value of assets acquired Accounts receivable $ 61,790 Other current assets 2,853 Oil and natural gas properties (1) 2,813,140 Ironwood equity investment 18,100 Total fair value of assets acquired 2,895,883 Fair value of liabilities assumed Accounts payable and other current liabilities (65,908 ) Asset retirement obligations (34,132 ) Deferred tax liability (13,639 ) Fair value of net assets acquired $ 2,782,204 (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. The recognized fair value of identifiable assets and acquired liabilities assumed in connection with the Subsequent GulfTex Acquisition, is as follows: (In thousands) 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 acquired and liabilities assumed: (In thousands) Fair value of assets acquired Other current assets $ 1,290 Oil and natural gas properties (1) 201,337 Total fair value of assets acquired 202,627 Fair value of liabilities assumed Asset retirement obligations and other current liabilities (9,666 ) Fair value of net assets acquired $ 192,961 (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.
Schedule of Pro Forma 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) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Total revenues $ 267,659 $ 723,768 Net income attributable to Class A Common Stock 57,891 151,316 Net income per share - basic 0.39 1.02 Net income per share - diluted 0.38 0.98

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Carrying Values and Fair Values of Financial Instruments Not Carried at Fair Value	The carrying value and fair value of the financial instrument that is not carried at fair value in the accompanying consolidated balance sheet as of September 30, 2019 is as follows: September 30, 2019 (In thousands) Carrying Value Fair Value Long-term debt $ 389,528 $ 404,000

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	(In thousands) September 30, 2019 Non-compete intangible assets $ 44,400 Accumulated amortization (16,923 ) Intangible assets, net $ 27,477 Weighted average amortization period (in years) 3.25

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Components of Income Tax Provision (Benefit)	The Company’s income tax provision consists of the following components: Successor Predecessor (In thousands) Three Months Ended Nine Months Ended July 31, 2018 July 1, 2018 January 1, 2018 Through Current: Federal $ — $ — $ — $ — $ — State 115 684 45 631 1,461 115 684 45 631 1,461 Deferred: Federal 3,135 11,588 3,493 — — State 279 177 — 135 324 3,414 11,765 3,493 135 324 Total provision $ 3,529 $ 12,449 $ 3,538 $ 766 $ 1,785

Long Term Debt (Tables)

Long Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Components of Debt	The Company’s debt is comprised of the following: (In thousands) September 30, 2019 Revolving credit facility $ — 6.0% Senior Notes due 2026 400,000 Total long-term debt 400,000 Less: Unamortized deferred financing cost (10,472 ) Total debt, net $ 389,528

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule of Lease Assets and Liabilities and Supplemental Information	(In thousands) September 30, 2019 Operating Leases Operating lease assets $ 4,772 Operating lease liabilities - current $ 2,724 Operating lease liabilities - long-term 2,039 Total operating lease liabilities $ 4,763 Weighted average remaining lease term (in years) 2.0 Weighted average discount rate 3.8 %
Schedule of Maturity of Lease Liabilities	Maturities of lease liabilities as of September 30, 2019 under the scope of ASC 842 are as follows: (In thousands) Maturity of Lease Liabilities (1) Operating Leases 2019 (remaining) $ 771 2020 2,653 2021 1,170 2022 165 2023 98 After 2023 91 Total lease payments $ 4,948 Less: Interest (185 ) Present value of lease liabilities $ 4,763 (1) As of December 31, 2018, minimum future contractual payments for long-term operating leases under the scope of ASC 840 were $881 thousand in 2019, $646 thousand in 2020, $198 thousand in 2021, $14 thousand in 2022, $15 thousand in 2023 and $63 thousand thereafter.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Schedule of Supplemental Cash Flow Disclosures	Supplemental cash flow disclosures are presented below: Successor Predecessor (In thousands) Nine Months Ended July 31, 2018 Through September 30, 2018 January 1, 2018 Through Supplemental non-cash operating activity: Cash paid for income taxes $ 390 $ — $ 336 Cash paid for interest 25,687 350 — Supplemental non-cash investing and financing activity: Accruals or liabilities for capital expenditures $ 37,241 $ 45,242 $ 38,028 Contingent Consideration issued in Business Combination — 149,700 — Non-Compete agreement entered into in Business Combination — 44,400 — Equity issuances in connection with acquisitions 33,693 1,481,695 — Non-cash deemed dividend related to warrant exchange 2,763 — — Supplemental non-cash lease operating activity: Right-of-use assets obtained in exchange for operating lease obligations $ 6,720 — —

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Restricted Stock Unit Activity	The table below summarizes restricted stock unit activity for the nine months ended September 30, 2019 . Restricted Stock Units Weighted Average Grant Date Fair Value Unvested restricted stock units, beginning of period 807,431 $ 13.97 Granted 585,659 $ 12.33 Vested 237,702 $ 14.58 Forfeited — — Unvested restricted stock units, end of period 1,155,388 $ 13.06
Schedule of Performance Stock Award and Unit Activity	The table below summarizes performance stock award and unit activity for the nine months ended September 30, 2019 . Performance Stock Units Weighted Average Grant Date Fair Value Unvested performance stock units, beginning of period 475,312 $ 14.58 Granted 267,482 $ 13.87 Vested 33,333 $ 14.58 Forfeited — — Unvested performance stock units, end of period 709,461 $ 14.31
Schedule of Assumptions Used to Calculate Grant Date Fair Value of PSUs	The following table summarizes the assumptions used to calculate the grant date fair value of these PSUs. Grant Date Fair Value Assumptions Expected term (in years) 2.85 - 2.67 Expected volatility 33.61% - 31.58% Risk-free interest rate 2.48% - 2.29%

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
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 Period as the Predecessor was not previously accounted for as a standalone legal entity and did not have publicly traded securities. (In thousands, except per share data) Three Months Ended September 30, 2019 Nine Months Ended July 31, 2018 Through September 30, 2018 Basic: Net Income attributable to Class A Common Stock $ 7,784 $ 39,316 $ 6,176 Weighted average number of common shares outstanding during the period - basic 166,872 160,051 151,992 Net income per common share - basic $ 0.05 $ 0.25 0.04 Diluted: Net Income attributable to Class A Common Stock $ 7,784 $ 39,316 $ 6,176 Weighted average number of common shares outstanding during the period - basic 166,872 160,051 151,992 Add: Dilutive effect warrants and stock based compensation 236 1,437 5,080 Weighted average number of common shares outstanding during the period - diluted 167,108 161,488 157,072 Net income per common share - diluted $ 0.05 $ 0.24 $ 0.04

Description of Business and B_2

Description of Business and Basis of Presentation (Details) $ / shares in Units, shares in Millions	Jul. 31, 2018USD ($)$ / sharesshares	Mar. 15, 2018subsidiary	Sep. 30, 2019$ / shares	Dec. 31, 2018$ / shares
Business Acquisition [Line Items]
Number of 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	$ 0.0001
Class B Common Stock
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001	$ 0.0001
Business Combination
Business Acquisition [Line Items]
Aggregate consideration, cash | $	$ 1,214,966,000
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%

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
General required payment period	30 days
Receivables from contracts with customers	$ 113,200,000	$ 100,100,000
Allowance for doubtful accounts	$ 0	$ 0

Acquisitions - Narrative (Deta

Acquisitions - Narrative (Details) $ in Thousands

May 31, 2019USD ($)shares

Mar. 29, 2019USD ($)shares

Mar. 14, 2019USD ($)

Feb. 05, 2019USD ($)shares

Sep. 28, 2018USD ($)

Aug. 31, 2018USD ($)shares

Jul. 31, 2018USD ($)trancheshares

Mar. 01, 2018USD ($)

Jul. 30, 2018USD ($)

Sep. 30, 2018USD ($)

Sep. 30, 2018USD ($)

Sep. 30, 2019USD ($)

Mar. 31, 2019

Dec. 31, 2018shares

Jul. 30, 2018USD ($)

Sep. 30, 2019USD ($)

Sep. 30, 2018USD ($)

Business Acquisition [Line Items]

Cash payment to fully settle earnout obligation | $

$ 26,000

$ 0

$ 0

Transaction costs incurred | $

$ 0

$ 22,366

$ 0

0

438

Loss related to settlement | $

$ (6,700)

$ 0

$ 0

Highlander Oil & Gas Holdings LLC (Highlander) | MGY Louisiana LLC

Business Acquisition [Line Items]

Percentage of units held

85.00%

85.00%

Karnes County Assets

Business Acquisition [Line Items]

Cash payments to acquire certain oil and natural gas properties, subject to customary closing adjustments | $

$ 36,300

Highlander Acquisition | Highlander Oil & Gas Holdings LLC (Highlander)

Business Acquisition [Line Items]

Cash consideration paid for asset | $

$ 50,900

Eocene-Tuscaloosa Zone, Ultra Deep Structure Gas Well | Highlander Oil & Gas Holdings LLC (Highlander)

Business Acquisition [Line Items]

Percent working interest acquired

72.00%

Gulf Coast Ultra Deep Royalty Trust | Highlander Oil & Gas Holdings LLC (Highlander)

Business Acquisition [Line Items]

Number of units acquired | shares

31,100,000

Class A Common Stock | Karnes County Assets

Business Acquisition [Line Items]

Shares issued as consideration to acquire certain oil and natural gas properties (in shares) | shares

3,100,000

EnerVest Business Combination

Business Acquisition [Line Items]

Cash consideration | $

$ 1,214,966

Transaction costs incurred | $

24,800

$ 34,300

Debt issuance costs incurred in connection with consummation of Business Combination | $

23,500

One time purchase of seismic license continuation | $

11,000

Loss related to settlement | $

$ 6,700

Total purchase price consideration | $

$ 2,782,204

EnerVest Business Combination | Non-Compete Agreement | Tranche One

Business Acquisition [Line Items]

Estimated economic life of intangible asset

2 years 6 months

EnerVest Business Combination | Non-Compete Agreement | Tranche Two

Business Acquisition [Line Items]

Estimated economic life of intangible asset

4 years

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

Number of tranches | tranche

2

EnerVest Business Combination | Class A Common Stock | Affiliate | Tranche One

Business Acquisition [Line Items]

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

2,000,000

EnerVest Business Combination | Class A Common Stock | Affiliate | Tranche Two

Business Acquisition [Line Items]

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

2,000,000

EnerVest Business Combination | Karnes County Contributors

Business Acquisition [Line Items]

Cash consideration | $

$ 911,500

Net cash payment from final settlement | $

$ (4,300)

Shares forfeited pursuant to Contribution and Merger Agreement (in shares) | shares

2,100,000

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

Business Acquisition [Line Items]

Term of contribution agreement

5 years

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

Shares forfeited pursuant to Contribution and Merger Agreement (in shares) | shares

1,600,000

EnerVest Business Combination | Karnes County Contributors | Class B Common Stock | Karnes County Contribution Agreement | Affiliate

Business Acquisition [Line Items]

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

9,400,000

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 | Magnolia LLC Units | Magnolia LLC

Business Acquisition [Line Items]

Shares forfeited pursuant to Contribution and Merger Agreement (in shares) | shares

1,600,000

EnerVest Business Combination | Karnes County Contributors | Magnolia LLC Units | Karnes County Contribution Agreement | Affiliate

Business Acquisition [Line Items]

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

9,400,000

EnerVest Business Combination | Karnes County Contributors | Magnolia LLC Units | Karnes County Contribution Agreement | Affiliate | Magnolia LLC

Business Acquisition [Line Items]

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

9,400,000

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

Shares forfeited pursuant to Contribution and Merger Agreement (in shares) | shares

500,000

EnerVest Business Combination | Karnes County Contributors | Class A Common Stock | Karnes County Contribution Agreement | Affiliate

Business Acquisition [Line Items]

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

13,000,000

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

3,600,000

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

Business Acquisition [Line Items]

Exchange ratio for equity interests issued

1

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]

Authorized amount of cash earnount payments | $

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

Business Acquisition [Line Items]

Cash consideration | $

$ 133,300

Total purchase price consideration | $

$ 191,500

Harvest | Class A Common Stock

Business Acquisition [Line Items]

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

4,200,000

Harvest | Harvest

Business Acquisition [Line Items]

Net cash payment from final settlement | $

$ 1,400

GulfTex Acquisition

Business Acquisition [Line Items]

Total purchase price consideration | $

$ 150,100

Acquisitions - Schedule of Pur

Acquisitions - Schedule of Purchase Consideration for Business Combination (Details) - USD ($) $ in Thousands, shares in Millions	Mar. 29, 2019	Jul. 31, 2018	Sep. 30, 2018	Jul. 30, 2018	Sep. 30, 2019
Business Acquisition [Line Items]
Stock consideration			$ 1,481,695	$ 0	$ 33,693
EnerVest Business Combination
Business Acquisition [Line Items]
Cash consideration		$ 1,214,966
Stock consideration		1,398,238
Fair value of contingent earnout purchase consideration		169,000
Total purchase price consideration		2,782,204
EnerVest Business Combination | Karnes County Contributors
Business Acquisition [Line Items]
Cash consideration		$ 911,500
Shares forfeited pursuant to Contribution and Merger Agreement (in shares)	2.1
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
Shares forfeited pursuant to Contribution and Merger Agreement (in shares)	1.6
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
Shares forfeited pursuant to Contribution and Merger Agreement (in shares)	0.5
EnerVest Business Combination | Magnolia LLC Units
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)		83.9
EnerVest Business Combination | Magnolia LLC Units | Karnes County Contributors
Business Acquisition [Line Items]
Equity interests issued in business combination (in shares)		83.9

Acquisitions - Summary of Allo

Acquisitions - Summary of Allocation of Purchase Consideration to Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Aug. 31, 2018	Jul. 31, 2018	Mar. 01, 2018
EnerVest Business Combination
Fair value of assets acquired
Accounts receivable		$ 61,790
Other current assets		2,853
Oil and natural gas properties		2,813,140
Ironwood equity investment		18,100
Total fair value of assets acquired		2,895,883
Fair value of liabilities assumed
Accounts payable and other current liabilities		(65,908)
Asset retirement obligations and other current liabilities		(34,132)
Deferred tax liability		(13,639)
Fair value of net assets acquired		$ 2,782,204
Harvest Acquisition
Fair value of assets acquired
Other current assets	$ 1,290
Oil and natural gas properties	201,337
Total fair value of assets acquired	202,627
Fair value of liabilities assumed
Asset retirement obligations and other current liabilities	(9,666)
Fair value of net assets acquired	$ 192,961
GulfTex Acquisition
Fair value of assets acquired
Accounts receivable			$ 10,501
Proved oil and natural gas properties			118,572
Unproved oil and natural gas properties			22,802
Fair value of liabilities assumed
Accounts payable and other current liabilities			(1,679)
Asset retirement obligations and other current liabilities			(57)
Fair value of net assets acquired			$ 150,139

Acquisitions - Schedule of Pro

Acquisitions - Schedule of Pro Forma Information (Details) - EnerVest Business Combination - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Total revenues	$ 267,659	$ 723,768
Net income attributable to Class A Common Stock	$ 57,891	$ 151,316
Net income per share - basic (in dollars per share)	$ 0.39	$ 1.02
Net income per share - diluted (in dollars per share)	$ 0.38	$ 0.98

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Predecessor) (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, 2019	Jul. 30, 2018	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (loss) on derivatives	$ 3,865	$ 0	$ 0	$ 0	$ (18,127)	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended
	Jul. 31, 2019	Jul. 25, 2019	Sep. 30, 2019
Carrying Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt			$ 389,528
Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt			$ 404,000
Class A Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock issued in exchange for Warrants (in shares)	9.2	9.2

Intangible Assets - Narrative

Intangible Assets - Narrative (Details) $ in Thousands	Jul. 31, 2018trancheshares	Sep. 30, 2019USD ($)
Non-Compete Agreement
Finite-Lived Intangible Assets [Line Items]
Estimated cost of intangible assets | $		$ 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 Business Combination | Non-Compete Agreement | Tranche One
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset	2 years 6 months
EnerVest Business Combination | Non-Compete Agreement | Tranche Two
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset	4 years
EnerVest Business Combination | 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
Number of tranches | tranche	2
EnerVest Business Combination | Class A Common Stock | Affiliate of EnerVest | Tranche One
Finite-Lived Intangible Assets [Line Items]
Number of shares authorized for issuance based on achievement of certain stock price thresholds (in shares)	2,000,000
EnerVest Business Combination | Class A Common Stock | Affiliate of EnerVest | Tranche Two
Finite-Lived Intangible Assets [Line Items]
Number of shares authorized for issuance based on achievement of certain stock price thresholds (in shares)	2,000,000

Intangible Assets - Schedule of

Intangible Assets - Schedule of Intangible Asset (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (16,923)
Intangible assets, net	$ 27,477	$ 38,356
Weighted average amortization period (in years)	3 years 3 months
Non-Compete Agreement
Finite-Lived Intangible Assets [Line Items]
Non-compete intangible assets	$ 44,400

Income Taxes - Narrative (Deta

Income Taxes - Narrative (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Income Tax Disclosure [Abstract]
U.S. federal income tax expense	$ 3,100,000	$ 11,600,000
Annual effective tax rate	16.90%	14.90%
Amount accrued for income tax uncertainties	$ 0	$ 0
Amount accrued for income tax interest and penalties	$ 0	$ 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, 2018	Sep. 30, 2019	Jul. 30, 2018	Sep. 30, 2019
Current:
Federal	$ 0		$ 0	$ 0	$ 0	$ 0
State	631		45	115	1,461	684
Current income tax provision (benefit)	631		45	115	1,461	684
Deferred:
Federal	0		3,493	3,135	0	11,588
State	135		0	279	324	177
Deferred income tax provision (benefit)	135	$ 3,493	3,493	3,414	324	11,765
Total provision	$ 766		$ 3,538	$ 3,529	$ 1,785	$ 12,449

Long Term Debt - Components of

Long Term Debt - Components of Debt (Details) - USD ($)	Sep. 30, 2019	Jul. 31, 2018
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000
Less: Unamortized deferred financing cost	(10,472,000)
Total debt, net	389,528,000
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)	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 400,000,000	$ 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	$ 11,700,000
Amortization period		5 years
Interest expense	1,100,000	$ 3,400,000
Outstanding borrowings	0	0
Line of Credit | RBL Facility | Magnolia Operating
Line of Credit Facility [Line Items]
Maximum commitments, aggregate principal amount	1,000,000,000	1,000,000,000
Initial borrowing base	$ 550,000,000	$ 550,000,000
Leverage ratio (less than)	4	4
Leverage ratio, minimum threshold for current ratio	3	3
Current ratio (greater than)	1	1
Line of Credit | Letter of Credit Sublimit | Magnolia Operating
Line of Credit Facility [Line Items]
Maximum commitments, aggregate principal amount	$ 100,000,000	$ 100,000,000

Long Term Debt - 2026 Senior N

Long Term Debt - 2026 Senior Notes Narrative (Details) - Senior Notes - 6.0% Senior Notes due 2026 - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jul. 31, 2018
Debt Instrument [Line Items]
Aggregate principal amount			$ 400,000,000
Stated interest rate	6.00%	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	$ 11,800,000
Interest expense	$ 6,300,000	$ 18,900,000

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Remaining lease term (up to)		8 years
Operating lease costs	$ 0.9	$ 2.1
Short-term lease costs	5.9	21.1
Variable lease costs	$ 0.6	2.5
Cash paid for amounts included in the measurement of lease liabilities in operating cash flows from operating leases		$ 2

Leases - Lease Assets and Liabi

Leases - Lease Assets and Liabilities and Supplemental Information (Details) $ in Thousands	Sep. 30, 2019USD ($)
Operating Leases
Operating lease assets	$ 4,772
Operating lease liabilities - current	2,724
Operating lease liabilities - long-term	2,039
Total operating lease liabilities	$ 4,763
Weighted average remaining lease term (in years)	2 years
Weighted average discount rate	3.80%

Leases - Maturity of Lease Liab

Leases - Maturity of Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Operating Leases
2019 (remaining)	$ 771
2020	2,653
2021	1,170
2022	165
2023	98
After 2023	91
Total lease payments	4,948
Less: Interest	(185)
Present value of lease liabilities	$ 4,763
Minimum Future Contractual Payments for Long-term Operating Leases, ASC 840
2019		$ 881
2020		646
2021		198
2022		14
2023		15
Thereafter		$ 63

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	Feb. 05, 2019	Jul. 31, 2019shares	Jul. 25, 2019shares	Jul. 30, 2018USD ($)	Sep. 30, 2019USD ($)vote$ / sharesshares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)voteshares	Sep. 30, 2019USD ($)voteshares	Jun. 30, 2019USD ($)	Mar. 31, 2019	Jul. 30, 2018USD ($)	Sep. 30, 2019USD ($)voteshares	Aug. 05, 2019shares	Jun. 07, 2019shares	Dec. 31, 2018shares
Class of Stock [Line Items]
Warrants outstanding (in shares)			31,700,000
Non-cash deemed dividend related to warrant exchange | $				$ 0		$ 0	$ 2,800	$ 2,763			$ 0	$ 2,763
Capitalized offering expenses | $							$ 2,200		$ 1,055
Number of shares authorized to be repurchased (in shares)													10,000,000
Total cost of shares repurchased | $								$ 9,722
Highlander
Class of Stock [Line Items]
Percentage of economic interest owned by noncontrolling interest holders										15.00%
MGY Louisiana LLC | Highlander
Class of Stock [Line Items]
Percentage of units held	85.00%									85.00%
Variable Interest Entity, Primary Beneficiary | Magnolia LLC
Class of Stock [Line Items]
Percentage of economic interest owned												64.60%
Percentage of economic interest owned by noncontrolling interest holders					35.40%		35.40%	35.40%				35.40%
Public Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)			21,700,000
Private Placement Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)			10,000,000
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				1,300,000,000			1,300,000,000
Common stock, shares issued (in shares)					168,260,000		168,260,000	168,260,000				168,260,000			156,333,000
Common stock, shares outstanding (in shares)					167,310,000		167,310,000	167,310,000				167,310,000			156,333,000
Number of votes for each share held | vote					1		1	1				1
Common stock issued in exchange for Warrants tendered in the Offer (in shares)														0.29
Aggregate shares issued (in shares)		9,200,000	9,200,000
Number of shares repurchased (in shares)					950,000
Average price paid per share (in dollars per share) | $ / shares					$ 10.23
Total cost of shares repurchased | $					$ 9,700
Class A Common Stock | Warrant Amendment
Class of Stock [Line Items]
Common stock issued in exchange for Warrants tendered in the Offer (in shares)														0.261
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)					225,000,000		225,000,000	225,000,000				225,000,000			225,000,000
Common stock, shares issued (in shares)					91,790,000		91,790,000	91,790,000				91,790,000			93,346,000
Common stock, shares outstanding (in shares)					91,790,000		91,790,000	91,790,000				91,790,000			93,346,000
Number of votes for each share held | vote					1		1	1				1

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (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, 2019	Sep. 30, 2019	Jul. 30, 2018	Sep. 30, 2019
Supplemental non-cash operating activity:
Cash paid for income taxes		$ 0			$ 336	$ 390
Cash paid for interest		350			0	25,687
Supplemental non-cash investing and financing activity:
Accruals or liabilities for capital expenditures		45,242			38,028	37,241
Contingent Consideration issued in Business Combination		149,700			0	0
Non-Compete agreement entered into in Business Combination		44,400			0	0
Equity issuances in connection with acquisitions		1,481,695			0	33,693
Non-cash deemed dividend related to warrant exchange	$ 0	0	$ 2,800	$ 2,763	0	2,763
Supplemental non-cash lease operating activity:
Right-of-use assets obtained in exchange for operating lease obligations		$ 0			$ 0	$ 6,720

Stock Based Compensation - Narr

Stock Based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Oct. 08, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2.8	$ 8.4
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Unrecognized compensation expense	12	$ 12
Weighted average period over which unrecognized compensation expense is expected to be recognized		2 years 1 month 6 days
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Unrecognized compensation expense	$ 7	$ 7
Weighted average period over which unrecognized compensation expense is expected to be recognized		2 years 1 month 6 days
Grant date fair value		$ 3.7
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)			11,800,000
Class A Common Stock | PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contingent right to receive common stock, number of shares receivable for each PSU (in shares)	1	1
Class A Common Stock | PSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		0.00%
Class A Common Stock | PSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		150.00%

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Stock Unit, Performance Stock Awards and Unit Activity (Details)	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Restricted Stock Units
Units
Unvested stock units, beginning of period (in shares) | shares	807,431
Granted (in shares) | shares	585,659
Vested (in shares) | shares	237,702
Forfeited (in shares) | shares	0
Unvested stock units, end of period (in shares) | shares	1,155,388
Weighted Average Grant Date Fair Value
Unvested stock units, beginning of period (in dollars per share) | $ / shares	$ 13.97
Granted (in dollars per share) | $ / shares	12.33
Vested (in dollars per share) | $ / shares	14.58
Forfeited (in dollars per share) | $ / shares	0
Unvested stock units, end of period (in dollars per share) | $ / shares	$ 13.06
Performance Stock Units
Units
Unvested stock units, beginning of period (in shares) | shares	475,312
Granted (in shares) | shares	267,482
Vested (in shares) | shares	33,333
Forfeited (in shares) | shares	0
Unvested stock units, end of period (in shares) | shares	709,461
Weighted Average Grant Date Fair Value
Unvested stock units, beginning of period (in dollars per share) | $ / shares	$ 14.58
Granted (in dollars per share) | $ / shares	13.87
Vested (in dollars per share) | $ / shares	14.58
Forfeited (in dollars per share) | $ / shares	0
Unvested stock units, end of period (in dollars per share) | $ / shares	$ 14.31

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Assumptions Used to Calculate Grant Date Fair Value of PSUs (Details) - PSUs	9 Months Ended
	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, maximum	33.61%
Expected volatility, minimum	31.58%
Risk-free interest rate, maximum	2.48%
Risk-free interest rate, minimum	2.29%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years 10 months 6 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years 8 months 2 days

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, 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, 2019	Jul. 30, 2018	Sep. 30, 2019
Basic:
Net Income attributable to Class A Common Stock	$ 46,738	$ 6,176	$ 7,784	$ 218,553	$ 39,316
Weighted average number of common shares outstanding during the period - basic (in shares)		151,992	166,872		160,051
Net income per common share - basic (in dollars per share)		$ 0.04	$ 0.05		$ 0.25
Diluted:
Net Income attributable to Class A Common Stock		$ 6,176	$ 7,784		$ 39,316
Weighted average number of common shares outstanding during the period - basic (in shares)		151,992	166,872		160,051
Add: Dilutive effect of warrants and stock based compensation (in shares)		5,080	236		1,437
Weighted average number of common shares outstanding during the period - diluted (in shares)		157,072	167,108		161,488
Net income per common share - diluted (in shares)		$ 0.04	$ 0.05		$ 0.24
Class A Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded due to antidilutive effect (in shares)		87,600	91,800		92,300

Related Party Transactions (Det

Related Party Transactions (Details) shares in Millions, $ in Millions	Jul. 31, 2018trancheregistration_statementdirector	Jul. 30, 2018USD ($)	Dec. 31, 2018shares	Jul. 30, 2018USD ($)
Registration Rights Agreement
Related Party Transaction [Line Items]
Number of independent directors prior to Business Combination | director	4
Number of registration statements | registration_statement	2
Stockholder Agreement | Karnes County Contributors | Affiliate
Related Party Transaction [Line Items]
Number of directors entitled to nominate to each committee of the Board | director	1
Stockholder Agreement | Karnes County Contributors | Affiliate | Higher End of Stock Ownership Threshold
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%
Stockholder Agreement | Karnes County Contributors | Affiliate | Lower End of Stock Ownership Threshold
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%
Karnes County Contribution Agreement | Karnes County Contributors | Affiliate | EnerVest Business Combination
Related Party Transaction [Line Items]
Term of contribution agreement	5 years
Number of tranches | tranche	3
Karnes County Contribution Agreement | Karnes County Contributors | Class A Common Stock | Affiliate | EnerVest Business Combination
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares) | shares			3.6
Karnes County Contribution Agreement | Karnes County Contributors | Class B Common Stock | Affiliate | EnerVest Business Combination
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares) | shares			9.4
Karnes County Contribution Agreement | Karnes County Contributors | Magnolia LLC Units | Affiliate | EnerVest Business Combination
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares) | shares			9.4
Karnes County Contribution Agreement | Karnes County Contributors | Magnolia LLC Units | Affiliate | EnerVest Business Combination | Magnolia LLC
Related Party Transaction [Line Items]
Additional shares issued upon meeting stock price thresholds (in shares) | shares			9.4
Management Fees | Karnes County Contributors | Affiliate
Related Party Transaction [Line Items]
Management fees incurred | $		$ 1.6		$ 11.6