Cover Page - shares	9 Months Ended
	Sep. 26, 2020	Oct. 23, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 26, 2020
Document Transition Report	false
Entity File Number	001-15943
Entity Registrant Name	CHARLES RIVER LABORATORIES INTERNATIONAL, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	06-1397316
Entity Address, Address Line One	251 Ballardvale Street
Entity Address, City or Town	Wilmington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01887
City Area Code	781
Local Phone Number	222-6000
Title of 12(b) Security	Common stock, $0.01 par value
Trading Symbol	CRL
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Smaller Reporting Company	false
Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		49,742,626
Entity Central Index Key	0001100682
Current Fiscal Year End Date	--12-26
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false