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Document and Entity Information - shares
 6 Months Ended
Jun. 27, 2015
Jul. 15, 2015
Document and Entity Information [Abstract]    
Entity Registrant Name CHARLES RIVER LABORATORIES INTERNATIONAL INC  
Entity Central Index Key 0001100682  
Current Fiscal Year End Date --12-26  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 27, 2015  
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   46,779,186