CONCENTRATIONS, SIGNIFICANT CUSTOMERS, COMMITMENTS AND CONTINGENCIES - Customer Concentrations (Details) - Customer concentration risk	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Revenues | Customer 1
Revenue, Major Customer
Concentration percentage (as a percent)	22.00%	18.00%
Revenues | Customer 1 | Black Oil
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 1 | Refining
Revenue, Major Customer
Concentration percentage (as a percent)	27.00%	25.00%
Revenues | Customer 1 | Recovery
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 2
Revenue, Major Customer
Concentration percentage (as a percent)	16.00%	9.00%
Revenues | Customer 2 | Black Oil
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 2 | Refining
Revenue, Major Customer
Concentration percentage (as a percent)	20.00%	13.00%
Revenues | Customer 2 | Recovery
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 3
Revenue, Major Customer
Concentration percentage (as a percent)	14.00%	7.00%
Revenues | Customer 3 | Black Oil
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 3 | Refining
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 3 | Recovery
Revenue, Major Customer
Concentration percentage (as a percent)	73.00%	28.00%
Revenues | Customer 4
Revenue, Major Customer
Concentration percentage (as a percent)	13.00%	15.00%
Revenues | Customer 4 | Black Oil
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Revenues | Customer 4 | Refining
Revenue, Major Customer
Concentration percentage (as a percent)	16.00%	20.00%
Revenues | Customer 4 | Recovery
Revenue, Major Customer
Concentration percentage (as a percent)	0.00%	0.00%
Receivables | Customer 1
Revenue, Major Customer
Concentration percentage (as a percent)	17.00%	16.00%
Receivables | Customer 2
Revenue, Major Customer
Concentration percentage (as a percent)	13.00%	11.00%
Receivables | Customer 3
Revenue, Major Customer
Concentration percentage (as a percent)	11.00%	0.00%
Receivables | Customer 4
Revenue, Major Customer
Concentration percentage (as a percent)	14.00%	0.00%