CONCENTRATIONS, SIGNIFICANT CUSTOMERS, COMMITMENTS AND CONTINGENCIES - Customer Concentrations (Details) - Customer concentration risk	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues | Customer 1
Revenue, Major Customer [Line Items]
Concentration percentage	47.00%	35.00%
Revenues | Customer 1 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	58.00%	41.00%
Revenues | Customer 1 | Refining
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 1 | Recovery
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 2
Revenue, Major Customer [Line Items]
Concentration percentage	10.00%	5.00%
Revenues | Customer 2 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	13.00%	6.00%
Revenues | Customer 2 | Refining
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 2 | Recovery
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 3
Revenue, Major Customer [Line Items]
Concentration percentage	4.00%	0.00%
Revenues | Customer 3 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 3 | Refining
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 3 | Recovery
Revenue, Major Customer [Line Items]
Concentration percentage	37.00%	0.00%
Revenues | Customer 4
Revenue, Major Customer [Line Items]
Concentration percentage	4.00%	12.00%
Revenues | Customer 4 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	5.00%	15.00%
Revenues | Customer 4 | Refining
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Revenues | Customer 4 | Recovery
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Receivables | Customer 1
Revenue, Major Customer [Line Items]
Concentration percentage	23.00%	28.00%
Receivables | Customer 2
Revenue, Major Customer [Line Items]
Concentration percentage	18.00%	9.00%
Receivables | Customer 3
Revenue, Major Customer [Line Items]
Concentration percentage	11.00%	0.00%
Receivables | Customer 4
Revenue, Major Customer [Line Items]
Concentration percentage	2.00%	12.00%