BUSINESS COMBINATIONS - Pro Forma Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Cognate BioServices, Inc.
Business Acquisition [Line Items]
Revenue	$ 914,607	$ 706,250	$ 1,767,096	$ 1,434,708
Net income attributable to common shareholders	$ 96,365	74,408	$ 138,712	85,249
HemaCare Corporation
Business Acquisition [Line Items]
Revenue		682,584		1,389,661
Net income attributable to common shareholders		$ 67,383		$ 123,088

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
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-Name Accounting Standards Codification
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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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