RESTRUCTURING AND ASSET IMPAIRMENTS - Restructuring Costs by Classification on the Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 749	$ 559
Cost of services provided and products sold (excluding amortization of intangible assets)
Restructuring Cost and Reserve [Line Items]
Restructuring costs	563	476
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring costs	186	83
Severance and Transition Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	562	330
Severance and Transition Costs | Cost of services provided and products sold (excluding amortization of intangible assets)
Restructuring Cost and Reserve [Line Items]
Restructuring costs	523	247
Severance and Transition Costs | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring costs	39	83
Asset Impairments and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	187	229
Asset Impairments and Other Costs | Cost of services provided and products sold (excluding amortization of intangible assets)
Restructuring Cost and Reserve [Line Items]
Restructuring costs	40	229
Asset Impairments and Other Costs | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 147	$ 0