Document and Entity Information - USD ($)
$ in Thousands
12 Months Ended
Aug. 25, 2018
Oct. 15, 2018
Feb. 25, 2017
Document And Entity Information [Abstract]      
Entity Registrant Name Simply Good Foods Co.    
Entity Central Index Key 0001702744    
Current Fiscal Year End Date --08-25    
Entity Filer Category Accelerated Filer    
Document Type 10-K    
Document Period End Date Aug. 25, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   80,849,248  
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 452,417