Cover Page - shares	3 Months Ended
	Sep. 30, 2020	Nov. 03, 2020
Cover [Abstract]
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	5100 East Skelly Drive, Suite 500
Entity File Number	1-15461
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, par value $0.01 per share
Document Transition Report	false
Document Quarterly Report	true
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	MTRX
Entity Registrant Name	MATRIX SERVICE CO
Entity Central Index Key	0000866273
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		26,468,781
Entity Address, City or Town	Tulsa
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	74135
City Area Code	918
Local Phone Number	838-8822
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Tax Identification Number	73-1352174