COMMITMENTS AND CONTINGENCIES (Self Insurance Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Product Liability Contingency [Line Items]
Retention for environmental impairment		$ 1,000
Annual aggregate self-insured corridor retention amount	$ 5,000
Self-Insurance Liabilities		$ 65,600	$ 59,400
Weighted average risk free discount rate for self insurance liabilities		0.29%	1.52%
Self Insurance Losses Expected [Abstract]
2021	22,896	$ 22,896
2022	13,751	13,751
2023	9,655	9,655
2024	6,448	6,448
2025	4,990	4,990
Thereafter	8,188	8,188
Undiscounted self-insurance liabilities	65,928	65,928
Less: Discount	(320)	(320)
Total self-insurance liabilities (included in accrued expenses)	$ 65,608	65,608
Minimum
Product Liability Contingency [Line Items]
Deductible medical insurance policy		800
Safety-Kleen
Product Liability Contingency [Line Items]
Deductible per occurrence for workers compensation		1,000
Deductible per occurrence for general liability		2,000
Deductible per occurrence for vehicle liability		$ 2,000