| Cover Document | Oct. 26, 2020 |
| Document Information [Line Items] | |
| Entity Central Index Key | 0001702744 |
| Entity Incorporation, State or Country Code | DE |
| Document Type | 8-K |
| Document Period End Date | Oct. 26, 2020 |
| Entity Registrant Name | The Simply Good Foods Company |
| Entity File Number | 001-38115 |
| Entity Tax Identification Number | 82-1038121 |
| Entity Address, Address Line One | 1225 17th Street, Suite 1000 |
| Entity Address, City or Town | Denver |
| Entity Address, State or Province | CO |
| Entity Address, Postal Zip Code | 80202 |
| City Area Code | 303 |
| Local Phone Number | 633-2840 |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | SMPL |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
