REMEDIAL LIABILITIES (Changes in Remedial Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Changes to remedial liabilities
Balance at the beginning of the period	$ 128,007	$ 131,992
Liabilities assumed in acquisitions		2,041
Measurement period adjustments from prior period acquisitions	504
Accretion	4,712	5,074
Changes in estimates recorded to statement of operations	45	(1,635)
Expenditures	(9,740)	(9,922)
Currency translation and other	940	457
Balance at the end of the period	124,468	128,007
Remedial Liabilities for Landfill Sites
Changes to remedial liabilities
Balance at the beginning of the period	1,777	2,327
Liabilities assumed in acquisitions		0
Measurement period adjustments from prior period acquisitions	0
Accretion	86	110
Changes in estimates recorded to statement of operations	(21)	(538)
Expenditures	(42)	(122)
Currency translation and other	0	0
Balance at the end of the period	1,800	1,777
Remedial Liabilities for Inactive Sites
Changes to remedial liabilities
Balance at the beginning of the period	64,151	63,613
Liabilities assumed in acquisitions		0
Measurement period adjustments from prior period acquisitions	0
Accretion	2,648	2,737
Changes in estimates recorded to statement of operations	(289)	1,520
Expenditures	(3,906)	(3,893)
Currency translation and other	2,738	174
Balance at the end of the period	65,342	64,151
Remedial Liabilities (Including Superfund) for Non-Landfill Operations
Changes to remedial liabilities
Balance at the beginning of the period	62,079	66,052
Liabilities assumed in acquisitions		2,041
Measurement period adjustments from prior period acquisitions	504
Accretion	1,978	2,227
Changes in estimates recorded to statement of operations	355	(2,617)
Expenditures	(5,792)	(5,907)
Currency translation and other	(1,798)	283
Balance at the end of the period	$ 57,326	$ 62,079