| Cover Document | Jul. 01, 2021 | Apr. 07, 2021 |
| Document Information [Line Items] | ||
| Entity Central Index Key | 0001702744 | |
| Entity Incorporation, State or Country Code | DE | |
| Document Type | 8-K | |
| Document Period End Date | Jul. 1, 2021 | |
| 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 |
