REVENUES - Geography (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of revenue
Revenue	$ 988,001	$ 933,854	$ 685,509
Operating Segment
Disaggregation of revenue
Revenue	988,001	933,854	685,509
Operating Segment | United States
Disaggregation of revenue
Revenue	861,255	835,318	589,127
Operating Segment | Canada
Disaggregation of revenue
Revenue	80,620	73,251	88,499
Operating Segment | EMEA
Disaggregation of revenue
Revenue	41,218	19,947	5,079
Operating Segment | Other
Disaggregation of revenue
Revenue	4,908	5,338	2,804
Operating Segment | Environmental Services
Disaggregation of revenue
Revenue	451,249	425,413	440,547
Operating Segment | Environmental Services | United States
Disaggregation of revenue
Revenue	374,414	355,226	354,625
Operating Segment | Environmental Services | Canada
Disaggregation of revenue
Revenue	76,835	70,187	85,922
Operating Segment | Field & Industrial Services
Disaggregation of revenue
Revenue	500,187	473,754	232,402
Operating Segment | Field & Industrial Services | United States
Disaggregation of revenue
Revenue	450,276	445,405	221,942
Operating Segment | Field & Industrial Services | Canada
Disaggregation of revenue
Revenue	3,785	3,064	2,577
Operating Segment | Field & Industrial Services | EMEA
Disaggregation of revenue
Revenue	41,218	19,947	5,079
Operating Segment | Field & Industrial Services | Other
Disaggregation of revenue
Revenue	4,908	5,338	2,804
Operating Segment | Energy Waste
Disaggregation of revenue
Revenue	36,565	34,687	12,560
Operating Segment | Energy Waste | United States
Disaggregation of revenue
Revenue	$ 36,565	$ 34,687	$ 12,560