| Cover Page | Apr. 02, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 2, 2021 |
| Entity Registrant Name | Maximus, Inc. |
| Entity Incorporation, State or Country Code | VA |
| Entity File Number | 1-12997 |
| Entity Tax Identification Number | 54-1000588 |
| Entity Address, Address Line One | 1891 Metro Center Drive |
| Entity Address, City or Town | Reston |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 20190 |
| City Area Code | 703 |
| Local Phone Number | 251-8500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, no par value |
| Trading Symbol | MMS |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001032220 |
