EQUITY AND NONCONTROLLING INTERESTS - Schedule of Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2024	Jul. 01, 2023	Jun. 29, 2024	Jul. 01, 2023
Numerator:
Net income	$ 94,261	$ 99,443	$ 168,743	$ 203,397
Less: Net income attributable to noncontrolling interests	180	2,423	1,702	3,246
Net income available to Charles River Laboratories International, Inc.	94,081	97,020	167,041	200,151
Calculation of net income per share attributable to common shareholders of Charles River Laboratories International, Inc.
Net income available to Charles River Laboratories International, Inc.	94,081	97,020	167,041	200,151
Less: Adjustment of redeemable noncontrolling interest	301	0	702	0
Less: Incremental dividends attributable to noncontrolling interest holders	3,792	0	9,022	0
Net income available to Charles River Laboratories International, Inc. common shareholders	$ 89,988	$ 97,020	$ 157,317	$ 200,151
Denominator:
Weighted-average shares outstanding - Basic (in shares)	51,551	51,216	51,494	51,157
Effect of dilutive securities:
Stock options, restricted stock units and performance share units (in shares)	295	251	316	225
Weighted-average shares outstanding - Diluted (in shares)	51,846	51,467	51,810	51,382
Anti-dilutive common stock equivalents (in shares)	506	594	482	589