Magnolia Oil & Gas (MGY) 10-Q 6 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Nov. 02, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
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	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		165,500,753
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		85,789,814

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 148,533	$ 182,633
Accounts receivable	61,243	105,775
Drilling advances	473	299
Other current assets	4,613	4,511
Total current assets	214,862	293,218
PROPERTY, PLANT AND EQUIPMENT
Oil and natural gas properties	2,105,774	3,815,221
Other	4,063	3,087
Accumulated depreciation, depletion and amortization	(939,888)	(701,551)
Total property, plant and equipment, net	1,169,949	3,116,757
OTHER ASSETS
Deferred financing costs, net	6,632	8,390
Equity method investment	21,789	19,730
Intangible assets, net	12,973	23,851
Other long-term assets	8,074	4,460
TOTAL ASSETS	1,434,279	3,466,406
CURRENT LIABILITIES
Accounts payable	63,475	79,428
Other current liabilities (Note 8)	60,987	95,780
Total current liabilities	124,462	175,208
LONG-TERM LIABILITIES
Long-term debt, net	390,787	389,835
Asset retirement obligations, net of current	100,800	93,524
Deferred taxes, net	0	77,834
Other long-term liabilities	6,049	1,476
Total long-term liabilities	497,636	562,669
COMMITMENTS AND CONTINGENCIES (Note 10)
Additional paid-in capital	1,709,043	1,703,362
Treasury Stock, at cost, 3,100 shares and 1,000 shares in 2020 and 2019, respectively	(23,240)	(10,277)
Retained earnings (Accumulated deficit)	(1,153,195)	82,940
Noncontrolling interest	279,547	952,478
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	1,434,279	3,466,406
Class A Common Stock
Common stock	17	17
Class B Common Stock
Common stock	$ 9	$ 9

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Treasury stock (in shares)	3,100,000	1,000,000
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,300,000,000	1,300,000,000
Common stock, shares issued (in shares)	168,676,000	168,318,000
Common stock, shares outstanding (in shares)	165,576,000	167,318,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	225,000,000	225,000,000
Common stock, shares issued (in shares)	85,790,000	85,790,000
Common stock, shares outstanding (in shares)	85,790,000	85,790,000

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
REVENUES
Total revenues	$ 121,067	$ 244,799	$ 385,271	$ 706,432
OPERATING EXPENSES
Lease operating expenses	18,802	24,344	61,275	70,752
Gathering, transportation, and processing	5,771	9,270	20,579	26,016
Taxes other than income	7,331	13,333	22,874	40,825
Exploration expense	701	3,924	563,589	10,017
Impairment of oil and natural gas properties	0	0	1,381,258	0
Asset retirement obligation accretion	1,501	1,394	4,403	4,095
Depreciation, depletion and amortization	44,731	143,894	238,273	385,942
Amortization of intangible assets	3,626	3,626	10,879	10,879
General and administrative expenses	16,663	17,345	50,472	52,651
Transaction related costs	0	0	0	438
Total operating costs and expenses	99,126	217,130	2,353,602	601,615
OPERATING INCOME (LOSS)	21,941	27,669	(1,968,331)	104,817
OTHER INCOME (EXPENSE)
Income from equity method investee	1,007	92	2,059	608
Interest expense, net	(7,333)	(6,896)	(21,345)	(21,611)
Loss on derivatives, net	(2,208)	0	(2,208)	0
Other income (expense), net	(51)	21	(510)	8
Total other income (expense)	(8,585)	(6,783)	(22,004)	(20,995)
INCOME (LOSS) BEFORE INCOME TAXES	13,356	20,886	(1,990,335)	83,822
Income tax expense (benefit)	(339)	3,529	(79,340)	12,449
NET INCOME (LOSS)	13,695	17,357	(1,910,995)	71,373
LESS: Net income (loss) attributable to noncontrolling interest	4,548	6,810	(674,860)	29,294
NET INCOME ATTRIBUTABLE TO MAGNOLIA	9,147	10,547	(1,236,135)	42,079
LESS: Non-cash deemed dividend related to warrant exchange	0	2,763	0	2,763
NET INCOME (LOSS) ATTRIBUTABLE TO CLASS A COMMON STOCK	$ 9,147	$ 7,784	$ (1,236,135)	$ 39,316
WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
Basic (in shares)	166,467	166,872	166,728	160,051
Diluted (in shares)	170,676	167,108	166,728	161,488
Class A Common Stock
OTHER INCOME (EXPENSE)
NET INCOME (LOSS) ATTRIBUTABLE TO CLASS A COMMON STOCK	$ 9,147	$ 7,784	$ (1,236,135)	$ 39,316
NET INCOME (LOSS) PER SHARE OF CLASS A COMMON STOCK
Basic (in dollars per share)	$ 0.05	$ 0.05	$ (7.41)	$ 0.25
Diluted (in dollars per share)	$ 0.05	$ 0.05	$ (7.41)	$ 0.24
WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
Basic (in shares)	166,467	166,872	166,728	160,051
Diluted (in shares)	170,676	167,108	166,728	161,488
Oil revenues
REVENUES
Total revenues	$ 95,677	$ 207,840	$ 311,153	$ 584,009
Natural gas revenues
REVENUES
Total revenues	14,895	21,243	44,238	71,208
Natural gas liquids revenues
REVENUES
Total revenues	$ 10,495	$ 15,716	$ 29,880	$ 51,215

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Class A Common Stock	Total Stockholders’ Equity	Total Stockholders’ EquityClass A Common Stock	Common StockClass A Common Stock	Common StockClass B Common Stock	Additional Paid In Capital	Treasury Stock	Treasury StockClass A Common Stock	Retained Earnings/ Accumulated Deficit	Noncontrolling Interest
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
Changes in ownership interest adjustment	(87)		(919)				(919)				832
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 owner	8,809										8,809
Net income (loss)	22,713		13,026							13,026	9,687
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 (loss)	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]
Stock based compensation expense	3,115		3,115				3,115
Changes in ownership interest adjustment	742		108				108				634
Common stock issued in connection with acquisition (in shares)					3,055
Common stock issued in connection with acquisition	33,693		33,693				33,693
Offering expenses incurred in connection with warrants exchange	(1,055)		(1,055)				(1,055)
Distributions to noncontrolling interest owners	(227)										(227)
Net income (loss)	31,303		18,506							18,506	12,797
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
Changes in ownership interest adjustment	(8,500)		28,215				28,215				(36,715)
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 and other, net (in shares)					189
Common stock issued related to stock based compensation and other, net	(532)		(532)				(532)
Class A Common Stock repurchases (in shares)								950
Class A Common Stock repurchases	(9,722)		(9,722)					$ (9,722)
Distributions to noncontrolling interest owners	(489)										(489)
Net income (loss)	17,357		10,547							10,547	6,810
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 Dec. 31, 2019					168,319	85,790		1,000
Balance at beginning of period at Dec. 31, 2019	2,728,529		1,776,051		$ 17	$ 9	1,703,362	$ (10,277)		82,940	952,478
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	2,879		2,879				2,879
Changes in ownership interest adjustment	0		(1,793)				(1,793)				1,793
Common stock issued related to stock based compensation and other, net (in shares)					154
Common stock issued related to stock based compensation and other, net	(452)		(452)				(452)
Class A Common Stock repurchases (in shares)									1,000
Class A Common Stock repurchases		$ (6,483)		$ (6,483)					$ (6,483)
Distributions to noncontrolling interest owners	(284)										(284)
Net income (loss)	(1,895,299)		(1,227,010)							(1,227,010)	(668,289)
Balance at end of period (in shares) at Mar. 31, 2020					168,473	85,790		2,000
Balance at end of period at Mar. 31, 2020	828,890		543,192		$ 17	$ 9	1,703,996	$ (16,760)		(1,144,070)	285,698
Balance at beginning of period (in shares) at Dec. 31, 2019					168,319	85,790		1,000
Balance at beginning of period at Dec. 31, 2019	2,728,529		1,776,051		$ 17	$ 9	1,703,362	$ (10,277)		82,940	952,478
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(1,910,995)
Balance at end of period (in shares) at Sep. 30, 2020					168,676	85,790		3,100
Balance at end of period at Sep. 30, 2020	812,181		532,634		$ 17	$ 9	1,709,043	$ (23,240)		(1,153,195)	279,547
Balance at beginning of period (in shares) at Mar. 31, 2020					168,473	85,790		2,000
Balance at beginning of period at Mar. 31, 2020	828,890		543,192		$ 17	$ 9	1,703,996	$ (16,760)		(1,144,070)	285,698
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	3,065		3,065				3,065
Changes in ownership interest adjustment	0		(907)				(907)				907
Common stock issued related to stock based compensation and other, net (in shares)					114
Common stock issued related to stock based compensation and other, net	(33)		(33)				(33)
Distributions to noncontrolling interest owners	(207)										(207)
Net income (loss)	(29,391)		(18,272)							(18,272)	(11,119)
Balance at end of period (in shares) at Jun. 30, 2020					168,587	85,790		2,000
Balance at end of period at Jun. 30, 2020	802,324		527,045		$ 17	$ 9	1,706,121	$ (16,760)		(1,162,342)	275,279
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	2,927		2,927				2,927
Changes in ownership interest adjustment	0		175				175				(175)
Common stock issued related to stock based compensation and other, net (in shares)					89
Common stock issued related to stock based compensation and other, net	(180)		(180)				(180)
Class A Common Stock repurchases (in shares)									1,100
Class A Common Stock repurchases		$ (6,480)		$ (6,480)					$ (6,480)
Distributions to noncontrolling interest owners	(105)										(105)
Net income (loss)	13,695		9,147							9,147	4,548
Balance at end of period (in shares) at Sep. 30, 2020					168,676	85,790		3,100
Balance at end of period at Sep. 30, 2020	$ 812,181		$ 532,634		$ 17	$ 9	$ 1,709,043	$ (23,240)		$ (1,153,195)	$ 279,547

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME (LOSS)	$ 13,695	$ 17,357	$ (1,910,995)	$ 71,373
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	44,731	143,894	238,273	385,942
Amortization of intangible assets	3,626	3,626	10,879	10,879
Exploration expense, non-cash			561,629	536
Impairment of oil and natural gas properties	0	0	1,381,258	0
Asset retirement obligation accretion	1,501	1,394	4,403	4,095
Amortization of deferred financing costs			2,710	2,644
Loss on derivatives, net	2,208	0	2,208	0
Deferred tax expense (benefit)	0	3,414	(77,834)	11,765
Stock based compensation			8,871	8,376
Other			(2,059)	(512)
Changes in operating assets and liabilities:
Accounts receivable			44,532	(6,937)
Accounts payable			(15,953)	16,034
Accrued liabilities			(15,468)	(22,379)
Drilling advances			(174)	10,205
Other assets and liabilities, net			(1,281)	(3,410)
Net cash provided by operating activities			230,999	488,611
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of EnerVest properties			0	4,250
Acquisitions, other			(73,702)	(93,221)
Additions to oil and natural gas properties			(157,325)	(351,467)
Changes in working capital associated with additions to oil and natural gas properties			(18,972)	(13,392)
Other investing			(842)	(247)
Net cash used in investing activities			(250,841)	(454,077)
CASH FLOW FROM FINANCING ACTIVITIES
Contributions from noncontrolling interest owners			0	7,301
Distributions to noncontrolling interest owners			(594)	(716)
Class A Common Stock repurchases			(12,962)	(9,722)
Other financing activities			(702)	(2,666)
Net cash used in financing activities			(14,258)	(5,803)
NET CHANGE IN CASH AND CASH EQUIVALENTS			(34,100)	28,731
Cash and cash equivalents – Beginning of period			182,633	135,758
Cash and cash equivalents – End of period	148,533	164,489	148,533	164,489
Supplemental non-cash operating activity:
Cash paid (received) for income taxes			(724)	390
Cash paid for interest			25,445	25,687
Supplemental non-cash investing and financing activity:
Accruals or liabilities for capital expenditures			21,750	37,241
Equity issuances in connection with acquisitions			0	33,693
Non-cash deemed dividend related to warrant exchange	$ 0	$ 2,763	0	2,763
Supplemental non-cash lease operating activity:
Right-of-use assets obtained in exchange for operating lease obligations			$ 5,500	$ 6,720

Description of Business and Bas

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Organization and Nature of Operations Magnolia Oil & Gas Corporation (the “Company” or “Magnolia”) is an independent oil and natural gas company engaged in the acquisition, development, exploration, and production of oil, natural gas, and natural gas liquid (“NGL”) reserves. The Company’s oil and natural gas properties are located primarily in Karnes County and the Giddings area 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 The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial reporting. Accordingly, certain disclosures normally included in an Annual Report on Form 10-K have been omitted. The consolidated financial statements and related notes included in this Quarterly Report should be read in conjunction with the Company’s consolidated and combined financial statements and related notes included in the Company’s Annual Report on Form 10-K for the period ended December 31, 2019 (the “2019 Form 10-K”). Except as disclosed herein, there have been no material changes to the information disclosed in the notes to the consolidated and combined financial statements included in the Company’s 2019 Form 10-K. In the opinion of management, all normal, recurring adjustments and accruals considered necessary to present fairly, in all material respects, the Company’s interim financial results, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. Certain reclassifications of prior period financial statements have been made to conform to current reporting practices. The consolidated financial statements include the accounts of the Company and its subsidiaries after elimination of intercompany transactions and balances. The Company’s interests in oil and natural gas exploration and production ventures and partnerships are proportionately consolidated. The Company reflects a noncontrolling interest representing primarily the interest owned by the Karnes County Contributors through their ownership of Magnolia LLC Units in the consolidated financial statements. The noncontrolling interest is presented as a component of equity. See Note 1 2 —Stockholders’ Equity for further discussion of the noncontrolling interest.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies As of September 30, 2020, the Company’s significant accounting policies are consistent with those discussed in Note 2 — Summary of Significant Accounting Policies of its consolidated and combined financial statements contained in the Company’s 2019 Form 10-K, with the exception of Accounts Receivable and Allowance for Expected Credit Losses and as noted below. Accounts Receivable and Allowance for Expected Credit Losses In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments-Credit Losses (Topic 326): “Measurement of Credit Losses on Financial Instruments.” For public business entities, the new standard became effective for annual reporting periods beginning after December 15, 2019, including interim periods within that reporting period. Magnolia adopted this standard on January 1, 2020. The standard changes the impairment model for most financial assets and certain other instruments, including trade and other receivables, and requires entities to use a new forward-looking expected loss model that will result in earlier recognition of allowance for losses. The Company’s receivables consist mainly of trade receivables from commodity sales and joint interest billings due from owners on properties the Company operates. The majority of these receivables have payment terms of 30 days or less. For receivables due from joint interest owners, the Company generally has the ability to withhold future revenue disbursements to recover non-payment of joint interest billings. From an evaluation of the Company’s existing credit portfolio, historical credit losses have been de minimis and are expected to remain so in the future assuming no substantial changes to the business or creditworthiness of Magnolia’s business partners. As expected, there was no material impact on the Company’s unaudited consolidated financial statements or disclosures upon adoption of this ASU. Recent Accounting Pronouncements On August 26, 2020, the SEC adopted amendments to its rules in Regulation S-K to streamline the disclosures, which registrants are required to make about business, legal proceedings and risk factors and to add new requirements for disclosures about human capital resources. The amendments take a principles-based approach that gives registrants flexibility to tailor disclosures to their circumstances. The final rules become effective November 9, 2020 and will be incorporated in the Company’s Annual Report on Form 10-K for the period ending December 31, 2020. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): “Simplifying the Accounting for Income Taxes,” which reduces the complexity of accounting for income taxes by removing certain exceptions to the general principles and also simplifying areas such as separate entity financial statements and interim recognition of enactment of tax laws or rate changes. This standard is effective for interim and annual periods beginning after December 15, 2020 and shall be applied on either a prospective basis, a retrospective basis for all periods presented, or a modified retrospective basis through a cumulative-effect adjustment to retained earnings depending on which aspects of the new standard are applicable to an entity. The Company is currently evaluating the effect of this standard, but does not expect the adoption of this guidance to have a material impact on its financial position, cash flows, or result of operations. In May 2020, the SEC adopted final rules that amend the financial statement disclosure requirements for significant business acquisitions and dispositions. Among other changes, the final rules modify the significance tests and improve the disclosure requirements for acquired or to be acquired businesses and related pro forma financial information, the periods those financial statements must cover, and the form and content of the pro forma financial information. The final rules do not modify requirements for the acquisition and disposition of significant amounts of assets that do not constitute a business. The final rules are effective January 1, 2021, but earlier compliance is permitted. The Company plans to comply with the final rules during 2020, if applicable.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition 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 are primarily comprised of 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. 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. Additionally, the Company’s product sales contracts do not give rise to material contract assets or contract liabilities. The Company’s receivables consist mainly of trade receivables from commodity sales and joint interest billings due from owners on properties the Company operates. Receivables from contracts with customers totaled $52.3 million as of September 30, 2020 and $100.4 million as of December 31, 2019. 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 statements of operations for all periods presented. 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, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions 2020 Acquisitions On February 21, 2020, the Company completed the acquisition of certain non-operated oil and natural gas assets located in Karnes and DeWitt Counties, Texas, for approximately $69.7 million in cash. The transaction was accounted for as an asset acquisition. 2019 Acquisitions On May 31, 2019, the Company completed the acquisition of certain oil and natural gas assets primarily located in Gonzales and Karnes Counties for approximately $36.3 million in cash 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 natural 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.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Magnolia currently utilizes natural gas costless collars to reduce its exposure to price volatility for a portion of its natural gas production volumes. The Company’s policies do not permit the use of derivative instruments for speculative purposes. The Company’s natural gas costless collar derivative contracts are indexed to the Houston Ship Channel. Under the Company’s costless collar contracts, each collar has an established floor price and ceiling price. When the settlement price is below the floor price, the counterparty is required to make a payment to the Company and when the settlement price is above the ceiling price, the Company is required to make a payment to the counterparty. When the settlement price is between the floor and the ceiling, there is no payment required. The Company has elected not to designate any of its derivative instruments as hedging instruments. Accordingly, changes in the fair value of the Company’s derivative instruments are recorded immediately to earnings as “Loss on derivatives, net” on the Company’s consolidated statement of operations. For the three and nine months ended September 30, 2020, the Company recognized a $2.2 million unrealized loss related to its derivative instrument. There were no cash settlements or realized gains or losses on the Company’s derivative instruments during the three and nine months ended September 30, 2020 and 2019. The Company had the following outstanding derivative contracts in place as of September 30, 2020: 2020 2021 Natural gas costless collars: Notional volume (MMBtu) 4,600,000 12,150,000 Weighted average floor price ($/MMBtu) $ 2.31 $ 2.31 Weighted average ceiling price ($/MMBtu) $ 3.00 $ 3.00 See Note 6 — F air Value Measurem ent for the fair value hierarchy of the Company’s derivative contracts.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
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 nonrecurring 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 Accounting Standards Codification (“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. Recurring Fair Value Measurements 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 at September 30, 2020 and December 31, 2019 is as follows: September 30, 2020 December 31, 2019 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Long-term debt $ 390,787 $ 392,000 $ 389,835 $ 412,000 The fair value of the 2026 Senior Notes at September 30, 2020 and December 31, 2019 is 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 business combinations and asset retirement obligations. Derivative Instruments The fair value of the Company’s natural gas costless collar derivative instruments are measured using an industry-standard pricing model and are provided by a third party. The inputs used in the third-party pricing model include quoted forward prices for natural gas, the contracted volumes, volatility factors, and time to maturity, which are considered Level 2 inputs. The Company’s derivative instruments are recorded at fair value within “Other current liabilities” on the Company’s consolidated balance sheet as of September 30, 2020. These fair values are recorded by netting asset and liability positions with the same counterparty and are subject to contractual terms, which provide for net settlement. There are no long-term derivative assets or liabilities as of September 30, 2020 and there were no outstanding derivative instruments as of December 31, 2019. The following table presents the classification of the outstanding derivative instruments and the fair value hierarchy table for the Company’s derivative assets and liabilities that are required to be measured at fair value on a recurring basis: Fair Value Measurements Using (In thousands) Level 1 Level 2 Level 3 Total Fair Value Netting Carrying Amount September 30, 2020 Current assets: Natural gas derivative instruments $ — $ 2,181 $ — $ 2,181 $ (2,181) $ — Current liabilities: Natural gas derivative instruments $ — $ 4,389 $ — $ 4,389 $ (2,181) $ 2,208 See Note 5 — Derivative Instruments for notional volumes and terms with the Company’s derivative contracts. Nonrecurring Fair Value Measurements The Company applies the provisions of the fair value measurement standard on a nonrecurring basis to its non-financial assets and liabilities, including oil and natural gas properties. These assets and liabilities are not measured at fair value on a recurring basis but are subject to fair value adjustments when facts and circumstances arise that indicate a need for remeasurement. During the first quarter of 2020, Magnolia recorded impairments of $1.9 billion related to proved and unproved properties as a result of a sharp decline in commodity prices. Proved property impairment of $1.4 billion is included in “Impairment of oil and natural gas properties” and unproved property impairment of $0.6 billion is included in “Exploration expense” on the Company’s consolidated statement of operations. Proved and unproved properties that were impaired had aggregate fair values of $0.8 billion and $0.3 billion, respectively. The fair values of these oil and natural gas properties were measured using the income approach based on inputs that are not observable in the market, and therefore, represent Level 3 inputs. The Company calculated the estimated fair values of its oil and natural gas properties using a discounted future cash flow model. Significant inputs associated with the calculation of discounted future net cash flows include estimates of future commodity prices based on NYMEX strip pricing adjusted for price differentials, estimates of proved oil and natural gas reserves and risk adjusted probable and possible reserves, estimates of future expected operating and capital costs, and a market participant based weighted average cost of capital of 10% for proved property impairments and 12% for unproved property impairments. 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 1 2 — Stockholders’ Equity for additional information.

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets Non-Compete Agreement On July 31, 2018, the Company and EnerVest, separate and apart from the Business Combination, entered into a non-compete agreement (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 July 31, 2022. 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 July 31, 2018 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 statements of operations. (In thousands) September 30, 2020 December 31, 2019 Non-compete intangible assets $ 44,400 $ 44,400 Accumulated amortization (31,427) (20,549) Intangible assets, net $ 12,973 $ 23,851 Weighted average amortization period (in years) 3.25 3.25

Other Current Liabilities

Other Current Liabilities	9 Months Ended
	Sep. 30, 2020
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	Other Current Liabilities The following table provides detail of the Company’s other current liabilities for the periods presented: (In thousands) September 30, 2020 December 31, 2019 Accrued capital expenditures $ 21,750 $ 40,722 Accrued general and administrative expenditures 9,703 9,753 Accrued ad valorem taxes 7,027 8,741 Other 22,507 36,564 Total Other current liabilities $ 60,987 $ 95,780

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt The Company’s debt is comprised of the following: (In thousands) September 30, 2020 December 31, 2019 Revolving credit facility $ — $ — Senior Notes due 2026 400,000 400,000 Total long-term debt 400,000 400,000 Less: Unamortized deferred financing cost (9,213) (10,165) Total debt, net $ 390,787 $ 389,835 Credit Facility In connection with the consummation of the Business Combination, Magnolia Operating entered into 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, 2020 was $450.0 million. On October 15, 2020, Magnolia Operating entered into a Borrowing Base Redetermination Agreement and Amendment No. 2 to the RBL Facility, which provided for, among other things, the reaffirmation of the borrowing base at $450.0 million as part of the semi-annual scheduled redetermination. 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, 2020, 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 statements of operations. The Company recognized interest expense related to the RBL Facility of $1.0 million and $1.1 million for the three months ended September 30, 2020 and 2019, respectively, and $3.2 million and $3.4 million for the nine months ended September 30, 2020 and 2019, respectively. The unamortized portion of the deferred financing costs are included in “Deferred financing costs, net” on the accompanying consolidated balance sheet as of September 30, 2020. The Company did not have any outstanding borrowings under its RBL Facility as of September 30, 2020. 2026 Senior Notes On July 31, 2018, the Issuers issued and sold $400.0 million aggregate principal amount of 2026 Senior Notes in a private placement under Rule 144A and Regulation S under the Securities Act of 1933. The 2026 Senior Notes were issued under the Indenture, dated as of July 31, 2018 (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 2026 Senior 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. These costs 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 statements 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, 2020. The Company recognized interest expense related to the 2026 Senior Notes of $6.3 million for each of the three months ended September 30, 2020 and 2019, and $19.0 million and $18.9 million for the nine months ended September 30, 2020 and 2019, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
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 Assets. The litigation is in the pre-trial 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, 2020, the Company does not believe the outcome of any such disputes or legal actions will have a material effect on its consolidated statements of operations, balance sheet, or cash flows. No amounts were accrued with respect to outstanding litigation at September 30, 2020 or September 30, 2019. Environmental Matters The Company, as an owner or lessee and operator of oil and natural 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 natural 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 The Company’s revenue, profitability, and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which depend on numerous factors beyond the Company’s control such as overall oil and natural gas production and inventories in relevant markets, economic conditions, the global political environment, regulatory developments, and competition from other energy sources. Oil and natural gas prices historically have been volatile and may be subject to significant fluctuations in the future. The coronavirus disease 2019 (“COVID-19”) pandemic and related economic repercussions have created significant volatility, uncertainty, and turmoil in the oil and natural gas industry. Oil demand has significantly deteriorated as a result of the virus outbreak and corresponding preventative measures taken around the world to mitigate the spread of the virus. The implications of the decrease in global demand for oil, coupled with the general oversupply, may have further negative effects on the Company’s business, such as production curtailment and reductions to its operating plans as a result of decreased prices and reduced storage capacity.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
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 it operates. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”). The CARES Act includes several significant business tax provisions that, among other things, allow businesses to carry back net operating losses (“NOL”) arising in 2018, 2019, and 2020 to the five prior tax years. Applying the NOL carryback provision resulted in an income tax benefit of $1.2 million during the nine months ended September 30, 2020. The difference in the U.S. federal statutory tax rate of 34% in 2017 compared to 21% in 2018 and thereafter resulted in a discrete benefit to the tax provision of approximately $0.4 million for the nine months ended September 30, 2020. The income tax expense or benefit recorded for the period is based on applying an estimated annual effective income tax rate to the net income or loss for the three and nine months ended September 30, 2020 and 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 or benefit may change as new events occur, more experience is obtained, additional information becomes known, or as the tax environment changes. The Company’s effective tax rate for the nine months ended September 30, 2020 and 2019 was 4.0% and 14.9%, respectively. During the nine months ended September 30, 2020, the Company’s effective tax rate was primarily impacted by the reversal of its federal and state deferred tax liabilities and the federal and state deferred tax assets generated from losses related to non-cash impairments of the carrying value of the Company’s oil and natural gas properties, offset by the recognition of valuation allowances. The primary differences between the annual effective tax rate and the federal statutory tax rate of 21.0% are income attributable to noncontrolling interest, the recognition of a valuation allowance on federal and state deferred tax assets, and state taxes. During the first quarter of 2020, the Company moved from a net deferred tax liability position to an estimated net deferred tax asset position resulting primarily from oil and natural gas impairments. As of September 30, 2020, the Company’s net deferred tax asset was $203.3 million. Management assessed whether it is more-likely-than-not that it will generate sufficient taxable income to realize its deferred income tax assets, including the investment in partnership and net operating loss carryforwards. In making this determination, the Company considered all available positive and negative evidence and made certain assumptions. The Company considered, among other things, the overall business environment, its historical earnings and losses, current industry trends, and its outlook for future years. As of September 30, 2020, the Company assessed the realizability of the deferred tax assets and recorded a full valuation allowance of $203.3 million. The Company’s income tax provision consists of the following components: Three Months Ended Nine Months Ended (In thousands) September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Current: Federal $ — $ — $ (1,167) $ — State (339) 115 (339) 684 (339) 115 (1,506) 684 Deferred: Federal — 3,135 (71,792) 11,588 State — 279 (6,042) 177 — 3,414 (77,834) 11,765 Income tax expense (benefit) $ (339) $ 3,529 $ (79,340) $ 12,449 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, 2020. 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.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Class A Common Stock At September 30, 2020, there were 168.7 million shares of Class A Common Stock issued and 165.6 million shares of Class A Common Stock outstanding. The holders of Class A Common Stock and Class B Common Stock vote together as a single class on all matters and are entitled one vote for each share held. There is no cumulative voting with respect to the election of directors, which results in the holders of more than 50% of the shares being able to elect all of the directors, subject to voting obligations under the Stockholder Agreement. In the event of a liquidation, dissolution, or winding up of Magnolia Oil & Gas Corporation, the holders of the Class A Common Stock 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 At September 30, 2020, there were 85.8 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 Magnolia LLC, the holders of the Class B Common Stock, through their ownership of Magnolia LLC Units, 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 units of Magnolia LLC, if any, having preference over the common units. 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 a tender and support agreement with the Company on June 7, 2019. 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” on the Company’s consolidated balance sheet. Share Repurchase Program On August 5, 2019, the Company’s board of directors authorized a share repurchase program of up to 10 million shares of Class A Common Stock. The program does not require purchases to be made within a particular timeframe. As of September 30, 2020, the Company had repurchased 3.1 million shares under the plan at a cost of $23.2 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, the exchange of Class B Common Stock (and corresponding Magnolia LLC Units) for Class A Common Stock, or the cancellation of Class B Common Stock (and corresponding Magnolia LLC Units). As of September 30, 2020, Magnolia owned approximately 66% of the interest in Magnolia LLC and the noncontrolling interest was 34%. In the first quarter of 2019, Magnolia Operating formed Highlander as a joint venture where MGY Louisiana LLC, a wholly owned subsidiary of Magnolia Operating, holds approximately 85% of the units in Highlander, with the remaining 15% attributable to noncontrolling interest.

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2020
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 grants stock based compensation awards in the form of restricted stock units (“RSUs”) and performance stock units (“PSUs”) to eligible employees and directors 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 net of forfeitures within “General and administrative expenses” on the consolidated statements of operations and was $2.9 million and $2.8 million for the three months ended September 30, 2020 and 2019, respectively, and $8.9 million and $8.4 million for the nine months ended September 30, 2020 and 2019, respectively. 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, in the case of awards to employees, and vest in full after one year, in the case of awards to directors. 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 that vest. RSUs are subject to restrictions on transfer and are generally subject to a risk of forfeiture if the award recipient ceases to be 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 RSUs as of September 30, 2020 was $10.5 million, which the Company expects to recognize over a weighted average period of 1.7 years. The table below summarizes RSU activity for the three and nine months ended September 30, 2020: Three Months Ended Nine Months Ended September 30, 2020 September 30, 2020 Restricted Stock Units Weighted Average Grant Date Fair Value Restricted Stock Units Weighted Average Grant Date Fair Value Unvested RSUs, beginning of period 1,637,445 $ 10.02 1,099,901 $ 12.97 Granted 21,552 6.46 874,919 7.14 Vested (110,548) 14.43 (426,371) 13.03 Forfeited (27,678) 10.07 (27,678) 10.07 Unvested RSUs, end of period 1,520,771 $ 9.65 1,520,771 $ 9.65 Performance Stock Units During the nine months ended September 30, 2020, the Company granted PSUs to certain employees. Each PSU, to the extent earned, represents the contingent right to receive one share of Class A Common Stock and the awardee may earn between zero and 150% of the target 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 a three-year performance period, the last day of which is also the vesting date. In addition to the TSR conditions, vesting of the PSUs is subject to the awardee’s continued employment through the date of settlement of the PSUs, which will occur within 60 days following the end of the performance period. Unrecognized compensation expense related to unvested PSUs as of September 30, 2020 was $5.1 million, which the Company expects to recognize over a weighted average period of 1.6 years. The table below summarizes PSU activity for the three and nine months ended September 30, 2020: Three Months Ended Nine Months Ended September 30, 2020 September 30, 2020 Performance Stock Units Weighted Average Grant Date Fair Value Performance Stock Units Weighted Average Grant Date Fair Value Unvested PSUs, beginning of period 1,086,419 $ 11.28 701,128 $ 14.31 Granted — — 401,958 6.14 Vested (25,260) 14.58 (41,927) 14.58 Forfeited (30,529) 10.77 (30,529) 10.77 Unvested PSUs, end of period 1,030,630 $ 11.22 1,030,630 $ 11.22 The grant date fair values of the PSUs granted were $2.5 million and $3.7 million during the nine months ended September 30, 2020 and 2019, respectively, calculated using a Monte Carlo simulation. The following table summarizes the assumptions used to calculate the grant date fair value of these PSUs. Nine Months Ended Grant Date Fair Value Assumptions September 30, 2020 September 30, 2019 Expected term (in years) 2.85 2.67-2.85 Expected volatility 33.50% 31.58% - 33.61% Risk-free interest rate 1.16% 2.29% - 2.48%

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share A reconciliation of the numerators and denominators of the basic and diluted per share computations follows: Three Months Ended Nine Months Ended (In thousands, except per share data) September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Basic: Net income (loss) attributable to Class A Common Stock $ 9,147 $ 7,784 $ (1,236,135) $ 39,316 Weighted average number of common shares outstanding during the period - basic 166,467 166,872 166,728 160,051 Net income (loss) per share of Class A Common Stock - basic $ 0.05 $ 0.05 $ (7.41) $ 0.25 Diluted: Net income (loss) attributable to Class A Common Stock $ 9,147 $ 7,784 $ (1,236,135) $ 39,316 Weighted average number of common shares outstanding during the period - basic 166,467 166,872 166,728 160,051 Add: Dilutive effect warrants, stock based compensation, and other 4,209 236 — 1,437 Weighted average number of common shares outstanding during the period - diluted 170,676 167,108 166,728 161,488 Net income (loss) per share of Class A Common Stock - diluted $ 0.05 $ 0.05 $ (7.41) $ 0.24 The Company excluded 85.8 million for the three and nine months ended September 30, 2020, 91.8 million for the three months ended September 30, 2019, and 92.3 million for the nine months ended September 30, 2019 of weighted average shares of Class A Common Stock issuable upon the exchange of the Class B Common Stock (and the corresponding Magnolia LLC Units) as the effect was anti-dilutive. In addition, the Company excluded 4.0 million contingent shares of Class A Common Stock issuable to an affiliate of EnerVest, provided EnerVest does not compete in the Market Area, and 0.2 million RSUs and PSU because the effect was anti-dilutive for the nine months ended September 30, 2020.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party TransactionsAs of September 30, 2020, 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.”

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial reporting. Accordingly, certain disclosures normally included in an Annual Report on Form 10-K have been omitted. The consolidated financial statements and related notes included in this Quarterly Report should be read in conjunction with the Company’s consolidated and combined financial statements and related notes included in the Company’s Annual Report on Form 10-K for the period ended December 31, 2019 (the “2019 Form 10-K”). Except as disclosed herein, there have been no material changes to the information disclosed in the notes to the consolidated and combined financial statements included in the Company’s 2019 Form 10-K. In the opinion of management, all normal, recurring adjustments and accruals considered necessary to present fairly, in all material respects, the Company’s interim financial results, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. Certain reclassifications of prior period financial statements have been made to conform to current reporting practices. The consolidated financial statements include the accounts of the Company and its subsidiaries after elimination of intercompany transactions and balances. The Company’s interests in oil and natural gas exploration and production ventures and partnerships are proportionately consolidated. The Company reflects a noncontrolling interest representing primarily the interest owned by the Karnes County Contributors through their ownership of Magnolia LLC Units in the consolidated financial statements. The noncontrolling interest is presented as a component of equity. See Note 1 2 —Stockholders’ Equity for further discussion of the noncontrolling interest.
Accounts Receivable and Allowance for Expected Credit Losses	Accounts Receivable and Allowance for Expected Credit Losses In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments-Credit Losses (Topic 326): “Measurement of Credit Losses on Financial Instruments.” For public business entities, the new standard became effective for annual reporting periods beginning after December 15, 2019, including interim periods within that reporting period. Magnolia adopted this standard on January 1, 2020. The standard changes the impairment model for most financial assets and certain other instruments, including trade and other receivables, and requires entities to use a new forward-looking expected loss model that will result in earlier recognition of allowance for losses. The Company’s receivables consist mainly of trade receivables from commodity sales and joint interest billings due from owners on properties the Company operates. The majority of these receivables have payment terms of 30 days or less. For receivables due from joint interest owners, the Company generally has the ability to withhold future revenue disbursements to recover non-payment of joint interest billings. From an evaluation of the Company’s existing credit portfolio, historical credit losses have been de minimis and are expected to remain so in the future assuming no substantial changes to the business or creditworthiness of Magnolia’s business partners. As expected, there was no material impact on the Company’s unaudited consolidated financial statements or disclosures upon adoption of this ASU.
Recent Accounting Pronouncements	Recent Accounting Pronouncements On August 26, 2020, the SEC adopted amendments to its rules in Regulation S-K to streamline the disclosures, which registrants are required to make about business, legal proceedings and risk factors and to add new requirements for disclosures about human capital resources. The amendments take a principles-based approach that gives registrants flexibility to tailor disclosures to their circumstances. The final rules become effective November 9, 2020 and will be incorporated in the Company’s Annual Report on Form 10-K for the period ending December 31, 2020. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): “Simplifying the Accounting for Income Taxes,” which reduces the complexity of accounting for income taxes by removing certain exceptions to the general principles and also simplifying areas such as separate entity financial statements and interim recognition of enactment of tax laws or rate changes. This standard is effective for interim and annual periods beginning after December 15, 2020 and shall be applied on either a prospective basis, a retrospective basis for all periods presented, or a modified retrospective basis through a cumulative-effect adjustment to retained earnings depending on which aspects of the new standard are applicable to an entity. The Company is currently evaluating the effect of this standard, but does not expect the adoption of this guidance to have a material impact on its financial position, cash flows, or result of operations. In May 2020, the SEC adopted final rules that amend the financial statement disclosure requirements for significant business acquisitions and dispositions. Among other changes, the final rules modify the significance tests and improve the disclosure requirements for acquired or to be acquired businesses and related pro forma financial information, the periods those financial statements must cover, and the form and content of the pro forma financial information. The final rules do not modify requirements for the acquisition and disposition of significant amounts of assets that do not constitute a business. The final rules are effective January 1, 2021, but earlier compliance is permitted. The Company plans to comply with the final rules during 2020, if applicable.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Derivative Contracts	The Company had the following outstanding derivative contracts in place as of September 30, 2020: 2020 2021 Natural gas costless collars: Notional volume (MMBtu) 4,600,000 12,150,000 Weighted average floor price ($/MMBtu) $ 2.31 $ 2.31 Weighted average ceiling price ($/MMBtu) $ 3.00 $ 3.00

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
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 at September 30, 2020 and December 31, 2019 is as follows: September 30, 2020 December 31, 2019 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Long-term debt $ 390,787 $ 392,000 $ 389,835 $ 412,000
Schedule of Classification of Outstanding Derivative Instruments and Fair Value Hierarchy	The following table presents the classification of the outstanding derivative instruments and the fair value hierarchy table for the Company’s derivative assets and liabilities that are required to be measured at fair value on a recurring basis: Fair Value Measurements Using (In thousands) Level 1 Level 2 Level 3 Total Fair Value Netting Carrying Amount September 30, 2020 Current assets: Natural gas derivative instruments $ — $ 2,181 $ — $ 2,181 $ (2,181) $ — Current liabilities: Natural gas derivative instruments $ — $ 4,389 $ — $ 4,389 $ (2,181) $ 2,208

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	(In thousands) September 30, 2020 December 31, 2019 Non-compete intangible assets $ 44,400 $ 44,400 Accumulated amortization (31,427) (20,549) Intangible assets, net $ 12,973 $ 23,851 Weighted average amortization period (in years) 3.25 3.25

Other Current Liabilities (Tabl

Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	The following table provides detail of the Company’s other current liabilities for the periods presented: (In thousands) September 30, 2020 December 31, 2019 Accrued capital expenditures $ 21,750 $ 40,722 Accrued general and administrative expenditures 9,703 9,753 Accrued ad valorem taxes 7,027 8,741 Other 22,507 36,564 Total Other current liabilities $ 60,987 $ 95,780

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Components of Debt	The Company’s debt is comprised of the following: (In thousands) September 30, 2020 December 31, 2019 Revolving credit facility $ — $ — Senior Notes due 2026 400,000 400,000 Total long-term debt 400,000 400,000 Less: Unamortized deferred financing cost (9,213) (10,165) Total debt, net $ 390,787 $ 389,835

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Components of Income Tax Provision (Benefit)	The Company’s income tax provision consists of the following components: Three Months Ended Nine Months Ended (In thousands) September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Current: Federal $ — $ — $ (1,167) $ — State (339) 115 (339) 684 (339) 115 (1,506) 684 Deferred: Federal — 3,135 (71,792) 11,588 State — 279 (6,042) 177 — 3,414 (77,834) 11,765 Income tax expense (benefit) $ (339) $ 3,529 $ (79,340) $ 12,449

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of RSU Activity	The table below summarizes RSU activity for the three and nine months ended September 30, 2020: Three Months Ended Nine Months Ended September 30, 2020 September 30, 2020 Restricted Stock Units Weighted Average Grant Date Fair Value Restricted Stock Units Weighted Average Grant Date Fair Value Unvested RSUs, beginning of period 1,637,445 $ 10.02 1,099,901 $ 12.97 Granted 21,552 6.46 874,919 7.14 Vested (110,548) 14.43 (426,371) 13.03 Forfeited (27,678) 10.07 (27,678) 10.07 Unvested RSUs, end of period 1,520,771 $ 9.65 1,520,771 $ 9.65
Schedule of PSU Activity	The table below summarizes PSU activity for the three and nine months ended September 30, 2020: Three Months Ended Nine Months Ended September 30, 2020 September 30, 2020 Performance Stock Units Weighted Average Grant Date Fair Value Performance Stock Units Weighted Average Grant Date Fair Value Unvested PSUs, beginning of period 1,086,419 $ 11.28 701,128 $ 14.31 Granted — — 401,958 6.14 Vested (25,260) 14.58 (41,927) 14.58 Forfeited (30,529) 10.77 (30,529) 10.77 Unvested PSUs, end of period 1,030,630 $ 11.22 1,030,630 $ 11.22
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. Nine Months Ended Grant Date Fair Value Assumptions September 30, 2020 September 30, 2019 Expected term (in years) 2.85 2.67-2.85 Expected volatility 33.50% 31.58% - 33.61% Risk-free interest rate 1.16% 2.29% - 2.48%

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
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: Three Months Ended Nine Months Ended (In thousands, except per share data) September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Basic: Net income (loss) attributable to Class A Common Stock $ 9,147 $ 7,784 $ (1,236,135) $ 39,316 Weighted average number of common shares outstanding during the period - basic 166,467 166,872 166,728 160,051 Net income (loss) per share of Class A Common Stock - basic $ 0.05 $ 0.05 $ (7.41) $ 0.25 Diluted: Net income (loss) attributable to Class A Common Stock $ 9,147 $ 7,784 $ (1,236,135) $ 39,316 Weighted average number of common shares outstanding during the period - basic 166,467 166,872 166,728 160,051 Add: Dilutive effect warrants, stock based compensation, and other 4,209 236 — 1,437 Weighted average number of common shares outstanding during the period - diluted 170,676 167,108 166,728 161,488 Net income (loss) per share of Class A Common Stock - diluted $ 0.05 $ 0.05 $ (7.41) $ 0.24

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
General required payment period	30 days
Receivables from contracts with customers	$ 52.3	$ 100.4

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) - USD ($) shares in Millions, $ in Millions	Feb. 21, 2020	May 31, 2019	Feb. 05, 2019	Mar. 31, 2019
Highlander Oil & Gas Holdings LLC (Highlander) | MGY Louisiana LLC
Business Acquisition [Line Items]
Percentage of units held			85.00%	85.00%
Karnes and DeWitt County Assets
Business Acquisition [Line Items]
Cash payments to acquire certain oil and natural gas properties	$ 69.7
Gonzales and Karnes County Assets
Business Acquisition [Line Items]
Cash payments to acquire certain oil and natural gas properties		$ 36.3
Gonzales and Karnes County Assets | Class A Common Stock
Business Acquisition [Line Items]
Shares issued as consideration to acquire certain oil and natural gas properties (in shares)		3.1
Highlander Acquisition | Highlander Oil & Gas Holdings LLC (Highlander)
Business Acquisition [Line Items]
Cash consideration paid for asset			$ 50.9
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 (in shares)			31.1

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Unrealized loss related to derivative instrument	$ 2,200,000		$ 2,200,000
Cash settlements on derivative instruments	0	$ 0	0	$ 0
Realized gains or losses on derivative instruments	$ 0	$ 0	$ 0	$ 0

Derivative Instruments - Outsta

Derivative Instruments - Outstanding Derivative Contracts (Details) - Natural Gas Costless Collars	9 Months Ended
	Sep. 30, 2020MMBTU$ / MMBTU
2020
Derivative [Line Items]
Notional volume (MMBtu) | MMBTU	4,600,000
Weighted average floor price ($/MMBtu)	2.31
Weighted average ceiling price ($/MMBtu)	3
2021
Derivative [Line Items]
Notional volume (MMBtu) | MMBTU	12,150,000
Weighted average floor price ($/MMBtu)	2.31
Weighted average ceiling price ($/MMBtu)	3

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments Not Carried at Fair Value (Details) - Level 1 - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 390,787	$ 389,835
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 392,000	$ 412,000

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) shares in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	Jul. 25, 2019shares	Sep. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019derivative
Fair Value Disclosures [Abstract]
Long term derivative assets		$ 0			$ 0
Long term derivative liabilities		0			0
Outstanding derivative instruments | derivative							0
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairments recorded related to proved and unproved oil and natural gas properties			$ 1,900,000,000
Proved property impairment		$ 0	1,400,000,000	$ 0	$ 1,381,258,000	$ 0
Unproved property impairment			$ 600,000,000
Class A Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate shares issued (in shares) | shares	9.2
Weighted Average | Cost of Capital | Market Participant Based
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market participant based weighted average cost of capital for proved property impairments			0.10
Market participant based weighted average cost of capital for unproved property impairments			0.12
Fair Value, Nonrecurring | Fair Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved properties impaired, fair values as of the most recent date of impairment			$ 800,000,000
Unproved properties impaired, fair values as of the most recent date of impairment			$ 300,000,000

Fair Value Measurements - Class

Fair Value Measurements - Classification of Outstanding Derivative Instruments and Fair Value Hierarchy (Details) - Fair Value, Recurring $ in Thousands	Sep. 30, 2020USD ($)
Current assets:
Natural gas derivative instruments	$ 2,181
Natural gas derivative instruments, Netting	(2,181)
Derivative Asset, Total	0
Current liabilities:
Natural gas derivative instruments	4,389
Natural gas derivative instruments, Netting	(2,181)
Derivative Liability, Total	2,208
Level 1
Current assets:
Natural gas derivative instruments	0
Current liabilities:
Natural gas derivative instruments	0
Level 2
Current assets:
Natural gas derivative instruments	2,181
Current liabilities:
Natural gas derivative instruments	4,389
Level 3
Current assets:
Natural gas derivative instruments	0
Current liabilities:
Natural gas derivative instruments	$ 0

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) $ in Thousands	Jul. 31, 2018trancheshares	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Non-Compete
Finite-Lived Intangible Assets [Line Items]
Estimated cost of intangible assets | $		$ 44,400	$ 44,400	$ 44,400
Non-Compete | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		2 years 6 months
Non-Compete | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset		4 years
EnerVest Business Combination | Non-Compete | Tranche One
Finite-Lived Intangible Assets [Line Items]
Estimated economic life of intangible asset	2 years 6 months
EnerVest Business Combination | Non-Compete | 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	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (31,427)	$ (20,549)
Intangible assets, net	$ 12,973	$ 23,851
Weighted average amortization period (in years)	3 years 3 months	3 years 3 months
Non-Compete
Finite-Lived Intangible Assets [Line Items]
Non-compete intangible assets	$ 44,400	$ 44,400	$ 44,400

Other Current Liabilities (Deta

Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Accrued capital expenditures	$ 21,750	$ 40,722
Accrued general and administrative expenditures	9,703	9,753
Accrued ad valorem taxes	7,027	8,741
Other	22,507	36,564
Total Other current liabilities	$ 60,987	$ 95,780

Long-term Debt - Components of

Long-term Debt - Components of Debt (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000	$ 400,000,000
Less: Unamortized deferred financing cost	(9,213,000)	(10,165,000)
Total debt, net	390,787,000	389,835,000
Line of Credit | Revolving credit facility
Debt Instrument [Line Items]
Total long-term debt	0	0
Senior Notes | Senior Notes due 2026
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000	$ 400,000,000

Long-term Debt - Credit Facilit

Long-term Debt - Credit Facility Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 400,000,000		$ 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	1,000,000	$ 1,100,000	$ 3,200,000	$ 3,400,000
Outstanding borrowings	0		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
Borrowing base	$ 450,000,000		$ 450,000,000
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 No

Long-term Debt - 2026 Senior Notes Narrative (Details) - Senior Notes - Senior Notes due 2026 - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jul. 31, 2018
Debt Instrument [Line Items]
Aggregate principal amount					$ 400,000,000
Stated interest rate					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	$ 6,300,000	$ 19,000,000	$ 18,900,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Amounts accrued with respect to outstanding litigation	$ 0	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax benefit resulting from applying NOL carryback provision	$ 1,200,000
Discrete benefit due to difference in U.S. federal tax rate	$ 400,000
Effective tax rate	4.00%	14.90%
Net deferred tax asset	$ 203,300,000
Valuation allowance	203,300,000
Liabilities for uncertain tax positions	0
Amounts incurred for interest and penalties	$ 0

Income Taxes - Components of In

Income Taxes - Components of Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Current:
Federal	$ 0	$ 0	$ (1,167)	$ 0
State	(339)	115	(339)	684
Current income tax provision	(339)	115	(1,506)	684
Deferred:
Federal	0	3,135	(71,792)	11,588
State	0	279	(6,042)	177
Deferred income tax provision	0	3,414	(77,834)	11,765
Income tax expense (benefit)	$ (339)	$ 3,529	$ (79,340)	$ 12,449

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ in Thousands	Feb. 05, 2019	Jul. 25, 2019shares	Sep. 30, 2020USD ($)voteshares	Mar. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019	Sep. 30, 2020USD ($)voteshares	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)voteshares	Dec. 31, 2019shares	Aug. 05, 2019shares	Jun. 07, 2019shares
Class of Stock [Line Items]
Warrants outstanding (in shares)		31,700,000
Non-cash deemed dividend related to warrant exchange | $			$ 0		$ 2,800	$ 2,763			$ 0	$ 2,763
Capitalized offering expenses | $					$ 2,200		$ 1,055
Total cost of shares repurchased | $						$ 9,722
Highlander
Class of Stock [Line Items]
Percentage of interest owned by noncontrolling interest holders								15.00%
VIE, Primary Beneficiary | Magnolia LLC
Class of Stock [Line Items]
Percentage of interest owned									66.00%
Percentage of interest owned by noncontrolling interest holders			34.00%						34.00%		34.00%
MGY Louisiana LLC | Highlander
Class of Stock [Line Items]
Percentage of units held	85.00%							85.00%
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 issued (in shares)			168,676,000						168,676,000		168,676,000	168,318,000
Common stock, shares outstanding (in shares)			165,576,000						165,576,000		165,576,000	167,318,000
Number of votes for each share held | vote			1						1		1
Common stock issued in exchange for Warrants tendered in the Offer (in shares)														0.29
Aggregate shares issued in exchange for all warrants		9,200,000
Number of shares authorized to be repurchased (in shares)													10,000,000
Number of shares repurchased (in shares)											3,100,000
Total cost of shares repurchased | $			$ 6,480	$ 6,483							$ 23,200
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 issued (in shares)			85,790,000						85,790,000		85,790,000	85,790,000
Common stock, shares outstanding (in shares)			85,790,000						85,790,000		85,790,000	85,790,000
Number of votes for each share held | vote			1						1		1

Stock Based Compensation - Narr

Stock Based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Oct. 08, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2.9	$ 2.8	$ 8.9	$ 8.4
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	10.5		$ 10.5
Weighted average period over which unrecognized compensation expense is expected to be recognized			1 year 8 months 12 days
RSUs | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
RSUs | Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Unrecognized compensation expense	$ 5.1		$ 5.1
Weighted average period over which unrecognized compensation expense is expected to be recognized			1 year 7 months 6 days
Settlement date, period following performance period			60 days
Grant date fair value			$ 2.5	$ 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 - RSU,

Stock Based Compensation - RSU, PSU Activity (Details) - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Restricted Stock Units
Units
Unvested stock units, beginning of period (in shares)	1,637,445	1,099,901
Granted (in shares)	21,552	874,919
Vested (in shares)	(110,548)	(426,371)
Forfeited (in shares)	(27,678)	(27,678)
Unvested stock units, end of period (in shares)	1,520,771	1,520,771
Weighted Average Grant Date Fair Value
Unvested stock units, beginning of period (in dollars per share)	$ 10.02	$ 12.97
Granted (in dollars per share)	6.46	7.14
Vested (in dollars per share)	14.43	13.03
Forfeited (in dollars per share)	10.07	10.07
Unvested stock units, end of period (in dollars per share)	$ 9.65	$ 9.65
Performance Stock Units
Units
Unvested stock units, beginning of period (in shares)	1,086,419	701,128
Granted (in shares)	0	401,958
Vested (in shares)	(25,260)	(41,927)
Forfeited (in shares)	(30,529)	(30,529)
Unvested stock units, end of period (in shares)	1,030,630	1,030,630
Weighted Average Grant Date Fair Value
Unvested stock units, beginning of period (in dollars per share)	$ 11.28	$ 14.31
Granted (in dollars per share)	0	6.14
Vested (in dollars per share)	14.58	14.58
Forfeited (in dollars per share)	10.77	10.77
Unvested stock units, end of period (in dollars per share)	$ 11.22	$ 11.22

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, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years 10 months 6 days
Expected volatility	33.50%
Expected volatility, minimum		31.58%
Expected volatility, maximum		33.61%
Risk-free interest rate	1.16%
Risk-free interest rate, minimum		2.29%
Risk-free interest rate, maximum		2.48%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		2 years 8 months 1 day
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		2 years 10 months 6 days

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic:
Net income (loss) attributable to Class A Common Stock	$ 9,147	$ 7,784	$ (1,236,135)	$ 39,316
Weighted average number of common shares outstanding during the period - basic (in shares)	166,467	166,872	166,728	160,051
Diluted:
Weighted average number of common shares outstanding during the period - basic (in shares)	166,467	166,872	166,728	160,051
Weighted average number of common shares outstanding during the period - diluted (in shares)	170,676	167,108	166,728	161,488
Class A Common Stock
Basic:
Net income (loss) attributable to Class A Common Stock	$ 9,147	$ 7,784	$ (1,236,135)	$ 39,316
Weighted average number of common shares outstanding during the period - basic (in shares)	166,467	166,872	166,728	160,051
Net income (loss) per share of Class A Common Stock - basic (in dollars per share)	$ 0.05	$ 0.05	$ (7.41)	$ 0.25
Diluted:
Net income (loss) attributable to Class A Common Stock	$ 9,147	$ 7,784	$ (1,236,135)	$ 39,316
Weighted average number of common shares outstanding during the period - basic (in shares)	166,467	166,872	166,728	160,051
Add: Dilutive effect of warrants, stock based compensation, and other (in shares)	4,209	236	0	1,437
Weighted average number of common shares outstanding during the period - diluted (in shares)	170,676	167,108	166,728	161,488
Net income (loss) per share of Class A Common Stock - diluted (in shares)	$ 0.05	$ 0.05	$ (7.41)	$ 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)	85,800	91,800	85,800	92,300
Contingent Shares of Class A Common Stock Issuable to EnerVest
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded due to antidilutive effect (in shares)			4,000
RSUs and PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded due to antidilutive effect (in shares)			200