REMEDIAL LIABILITIES (Changes in Remedial Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Changes to remedial liabilities
Balance at the beginning of the period	$ 121,017	$ 124,468
Accretion	4,535	4,702
Changes in estimates recorded to consolidated statement of operations	(3,017)	687
Expenditures	(8,862)	(7,834)
Currency translation and other	500	(1,006)
Balance at the end of the period	114,173	121,017
Remedial Liabilities for Landfill Sites
Changes to remedial liabilities
Balance at the beginning of the period	1,838	1,800
Accretion	88	86
Changes in estimates recorded to consolidated statement of operations	(17)	(1)
Expenditures	(59)	(47)
Currency translation and other	1	0
Balance at the end of the period	1,851	1,838
Remedial Liabilities for Inactive Sites
Changes to remedial liabilities
Balance at the beginning of the period	65,315	65,342
Accretion	2,639	2,745
Changes in estimates recorded to consolidated statement of operations	(913)	130
Expenditures	(5,079)	(3,759)
Currency translation and other	29	857
Balance at the end of the period	61,991	65,315
Remedial Liabilities (Including Superfund) for Non-Landfill Operations
Changes to remedial liabilities
Balance at the beginning of the period	53,864	57,326
Accretion	1,808	1,871
Changes in estimates recorded to consolidated statement of operations	(2,087)	558
Expenditures	(3,724)	(4,028)
Currency translation and other	470	(1,863)
Balance at the end of the period	$ 50,331	$ 53,864