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Document and Entity Information - shares
 6 Months Ended
Jul. 01, 2018
Jul. 24, 2018
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jul. 01, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Trading Symbol BGFV  
Entity Registrant Name BIG 5 SPORTING GOODS CORP  
Entity Central Index Key 0001156388  
Current Fiscal Year End Date --12-30  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   21,431,124