REVENUES - Treatment and Disposal Revenue (Details) - T	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Technical Services | Minimum
Disaggregation of revenue
Revenue Contract Term			1 year
Remediation | Minimum
Disaggregation of revenue
Revenue Contract Term			1 year
Event Business | Treatment and disposal
Disaggregation of revenue
Threshold Tons of Non-recurring projects			1,000
Revenue (in percent)	19.00%	23.00%	18.00%	19.00%
Base Business | Treatment and disposal
Disaggregation of revenue
Revenue (in percent)	81.00%	77.00%	82.00%	81.00%