RESTRUCTURING AND ASSET IMPAIRMENTS - Severance and Retention Costs by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Segment Reporting Information [Line Items]
Restructuring costs	$ 13,839	$ 7,568	$ 4,778
Total reportable segments | RMS
Segment Reporting Information [Line Items]
Restructuring costs	3,110	0	291
Total reportable segments | DSA
Segment Reporting Information [Line Items]
Restructuring costs	7,307	1,063	1,604
Total reportable segments | Manufacturing
Segment Reporting Information [Line Items]
Restructuring costs	3,032	1,227	2,883
Unallocated corporate
Segment Reporting Information [Line Items]
Restructuring costs	$ 390	$ 5,278	$ 0