Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 02, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	MR
Entity Registrant Name	Montage Resources Corporation
Entity Central Index Key	0001600470
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36511
Entity Tax Identification Number	46-4812998
Entity Address, Address Line One	122 West John Carpenter Freeway
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Irving
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75039
City Area Code	469
Local Phone Number	444-1647
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		36,023,973
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, Par Value $0.01 Per Share
Security Exchange Name	NYSE
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false