| Cover Page Document | Sep. 30, 2020 |
| Cover Page [Abstract] | |
| Pre-commencement Issuer Tender Offer | false |
| Pre-commencement Tender Offer | false |
| Soliciting Material | false |
| Written Communications | false |
| Document Type | 8-K |
| Entity Central Index Key | 0000866273 |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-15461 |
| Entity Tax Identification Number | 73-1352174 |
| Entity Address, Address Line One | 5100 East Skelly Drive, Suite 500 |
| Entity Address, Postal Zip Code | 74135 |
| Trading Symbol | MTRX |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Document Period End Date | Sep. 30, 2020 |
| Entity Registrant Name | Matrix Service Co |
| City Area Code | 918 |
| Local Phone Number | 838-8822 |
| Entity Emerging Growth Company | false |
| Entity Address, City or Town | Tulsa |
| Entity Address, State or Province | OK |
