COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	6 Months Ended
Jun. 30, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Increase in lease obligations	$ 40.1

Operating Leases, Future Minimum Payments, Due in Next Five Years, Increase

No definition available.

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Namespace Prefix:	crl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration