REMEDIAL LIABILITIES (Estimates) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) site facility	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Site Contingency [Line Items]
Remedial Liability	$ 114,173	$ 121,017	$ 124,468
% of Total	100.00%
Reasonably possible additional liabilities	$ 22,129
Facilities now used in active conduct of the Company's business (39 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 44,381
% of Total	38.90%
Reasonably possible additional liabilities	$ 10,691
Number of facility by type | facility	39
Inactive facilities not now used in active conduct of the Company's business but most of which were acquired because the assumption of remedial liabilities for such facilities was part of the purchase price for the CSD assets (37 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 61,991
% of Total	54.30%
Reasonably possible additional liabilities	$ 10,658
Number of facility by type | facility	37
Superfund sites owned by third parties (17 sites)
Site Contingency [Line Items]
Remedial Liability	$ 7,801
% of Total	6.80%
Reasonably possible additional liabilities	$ 780
Number of facility by type | site	17
Superfund sites owned by third parties (17 sites) | Various
Site Contingency [Line Items]
Remedial Liability	$ 7,801
% of Total	6.80%
Reasonably possible additional liabilities	$ 780
Number of facility by type | site	17
Closed incinerator and landfill | Baton Rouge LA
Site Contingency [Line Items]
Remedial Liability	$ 22,690
% of Total	19.90%
Reasonably possible additional liabilities	$ 3,975
Closed incinerator | Bridgeport, NJ
Site Contingency [Line Items]
Remedial Liability	$ 18,191
% of Total	15.90%
Reasonably possible additional liabilities	$ 2,578
Idled incinerator and legal proceedings | Mercier, Quebec
Site Contingency [Line Items]
Remedial Liability	$ 10,761
% of Total	9.40%
Reasonably possible additional liabilities	$ 1,098
Operating solvent recycling center | Linden, NJ
Site Contingency [Line Items]
Remedial Liability	$ 7,312
% of Total	6.40%
Reasonably possible additional liabilities	$ 762
All other incinerators, landfills, wastewater treatment facilities and service centers (72 facilities) | Various
Site Contingency [Line Items]
Remedial Liability	$ 47,418
% of Total	41.60%
Reasonably possible additional liabilities	$ 12,936
Number of facility by type | facility	72