WORKERS' COMPENSATION INSURANCE AND RESERVES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 30, 2018
Workers' Compensation Deductible Limit [Line Items]
Workers' compensation claim deductible limit			$ 2.0
Weighted average period - claim payments below deductible limit			4 years 6 months
Payments made against self-insured claims			$ 32.6	$ 36.1
Weighted average period - claim payments and receivables above deductible limit			16 years
Excess claims	$ 47.3		$ 47.3		$ 48.2
Workers compensation expense	$ 16.3	$ 17.8	$ 28.2	$ 34.4
Below limit
Workers' Compensation Deductible Limit [Line Items]
Workers' compensation discount			2.10%		2.00%
Above Limit
Workers' Compensation Deductible Limit [Line Items]
Workers' compensation discount			2.90%		2.90%