REMEDIAL LIABILITIES (Estimates) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) site facility	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Site Contingency [Line Items]
Remedial Liability	$ 121,017	$ 124,468	$ 128,007
% of Total	100.00%
Reasonably possible additional liabilities	$ 22,770
Legal and Administrative Proceedings
Site Contingency [Line Items]
Remedial Liability	17,900
Reasonably possible additional liabilities	1,800
Facilities now used in active conduct of the Company's business (41 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 48,506
% of Total	40.10%
Reasonably possible additional liabilities	$ 11,171
Number of facility by type | facility	41
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 (35 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 64,344
% of Total	53.20%
Reasonably possible additional liabilities	$ 10,782
Number of facility by type | facility	35
Superfund sites owned by third parties (17 sites)
Site Contingency [Line Items]
Remedial Liability	$ 8,167
% of Total	6.70%
Reasonably possible additional liabilities	$ 817
Number of facility by type | site	17
Superfund sites owned by third parties (17 sites) | Various
Site Contingency [Line Items]
Remedial Liability	$ 8,167
% of Total	6.70%
Reasonably possible additional liabilities	$ 817
Number of facility by type | site	17
Closed incinerator and landfill | Baton Rouge LA
Site Contingency [Line Items]
Remedial Liability	$ 23,314
% of Total	19.30%
Reasonably possible additional liabilities	$ 3,963
Closed incinerator | Bridgeport, NJ
Site Contingency [Line Items]
Remedial Liability	$ 18,616
% of Total	15.40%
Reasonably possible additional liabilities	$ 2,577
Idled incinerator and legal proceedings | Mercier Quebec
Site Contingency [Line Items]
Remedial Liability	$ 9,809
% of Total	8.10%
Reasonably possible additional liabilities	$ 1,037
Operating solvent recycling center | Linden, NJ
Site Contingency [Line Items]
Remedial Liability	$ 7,487
% of Total	6.20%
Reasonably possible additional liabilities	$ 790
All other incinerators, landfills, wastewater treatment facilities and service centers (72 facilities) | Various
Site Contingency [Line Items]
Remedial Liability	$ 53,624
% of Total	44.30%
Reasonably possible additional liabilities	$ 13,586
Number of facility by type | facility	72