REMEDIAL LIABILITIES (Estimates) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) site facility	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Site Contingency [Line Items]
Remedial Liability	$ 124,468	$ 128,007	$ 131,992
% of Total	100.00%
Reasonably possible additional liabilities	$ 23,053
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 (44 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 54,193
% of Total	43.50%
Reasonably possible additional liabilities	$ 11,747
Number of facility by type | facility	44
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 (38 facilities)
Site Contingency [Line Items]
Remedial Liability	$ 62,706
% of Total	50.40%
Reasonably possible additional liabilities	$ 10,549
Number of facility by type | facility	38
Superfund sites owned by third parties (16 sites)
Site Contingency [Line Items]
Remedial Liability	$ 7,569
% of Total	6.10%
Reasonably possible additional liabilities	$ 757
Number of facility by type | site	16
Superfund sites owned by third parties (16 sites) | Various
Site Contingency [Line Items]
Remedial Liability	$ 7,569
% of Total	6.10%
Reasonably possible additional liabilities	$ 757
Number of facility by type | site	16
Closed incinerator and landfill | Baton Rouge LA
Site Contingency [Line Items]
Remedial Liability	$ 23,357
% of Total	18.80%
Reasonably possible additional liabilities	$ 3,938
Closed incinerator | Bridgeport, NJ
Site Contingency [Line Items]
Remedial Liability	$ 18,394
% of Total	14.80%
Reasonably possible additional liabilities	$ 2,534
Idled incinerator and legal proceedings | Mercier Quebec
Site Contingency [Line Items]
Remedial Liability	$ 10,414
% of Total	8.40%
Reasonably possible additional liabilities	$ 1,105
Operating solvent recycling center | Linden, NJ
Site Contingency [Line Items]
Remedial Liability	$ 7,678
% of Total	6.20%
Reasonably possible additional liabilities	$ 825
All other incinerators, landfills, wastewater treatment facilities and service centers (78 facilities) | Various
Site Contingency [Line Items]
Remedial Liability	$ 57,056
% of Total	45.70%
Reasonably possible additional liabilities	$ 13,894
Number of facility by type | facility	78