BUSINESS ACQUISITIONS - Acquired Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 06, 2017	Dec. 30, 2018	Dec. 31, 2017
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value		$ 0	$ 92,900
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value		0	38,200
Non-compete agreement
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value		$ 0	$ 20
GNP
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value	$ 131,120
Weighted average useful life	15 years 2 months 12 days
GNP | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value	$ 92,900
Weighted average useful life	13 years
GNP | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value	$ 38,200
Weighted average useful life	20 years
GNP | Non-compete agreement
Acquired Finite-Lived Intangible Assets [Line Items]
Total fair value	$ 20
Weighted average useful life	3 years