Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Sep. 01, 2020	Dec. 31, 2019
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Jun. 30, 2020
Amendment Flag	false
Document Transition Report	false
Entity File Number	001-15461
Entity Registrant Name	MATRIX SERVICE CO
Entity Central Index Key	0000866273
Current Fiscal Year End Date	--06-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	73-1352174
Entity Address, Address Line One	5100 E. Skelly Drive,
Entity Address, Address Line Two	Suite 500
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
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	MTRX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 599
Entity Common Stock, Shares Outstanding		26,460,196