GOODWILL AND INTANGIBLE ASSETS - Amortized Intangible Assets - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018	Dec. 29, 2018
Components of amortized intangible assets
Gross Carrying Amount	$ 272,339		$ 272,339		$ 251,141
Accumulated Amortization	152,965		152,965		143,908
Amortization expense for intangible assets	4,632	$ 3,572	9,022	$ 7,455
Estimated amortization expense
2019	17,226		17,226
2020	17,004		17,004
2021	15,503		15,503
2022	13,356		13,356
2023	11,610		11,610
Customer Relationships
Components of amortized intangible assets
Gross Carrying Amount	241,076		241,076		219,508
Accumulated Amortization	140,674		$ 140,674		$ 132,180
Weighted Average Life			13 years		13 years
Patents & Proprietary Technology
Components of amortized intangible assets
Gross Carrying Amount	23,619		$ 23,619		$ 23,662
Accumulated Amortization	5,624		$ 5,624		$ 4,837
Weighted Average Life			14 years		14 years
Other
Components of amortized intangible assets
Gross Carrying Amount	7,644		$ 7,644		$ 7,971
Accumulated Amortization	$ 6,667		$ 6,667		$ 6,891
Weighted Average Life			5 years		5 years