| Cover Page | Oct. 21, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Oct. 21, 2019 |
| Entity Registrant Name | CHARLES RIVER LABORATORIES INTERNATIONAL, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-15943 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001100682 |
| Amendment Flag | false |
