CONCENTRATIONS, SIGNIFICANT CUSTOMERS, COMMITMENTS AND CONTINGENCIES - Customer Concentrations (Details) - Customer concentration risk	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Revenues | Customer 1
Revenue, Major Customer [Line Items]
Concentration percentage	35.00%	37.00%
Revenues | Customer 1 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	41.00%	47.00%
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	12.00%	8.00%
Revenues | Customer 2 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	14.00%	10.00%
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	8.00%	0.00%
Revenues | Customer 3 | Black Oil
Revenue, Major Customer [Line Items]
Concentration percentage	10.00%	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	0.00%	0.00%
Receivables | Customer 1
Revenue, Major Customer [Line Items]
Concentration percentage	25.00%	37.00%
Receivables | Customer 2
Revenue, Major Customer [Line Items]
Concentration percentage	0.00%	0.00%
Receivables | Customer 3
Revenue, Major Customer [Line Items]
Concentration percentage	15.00%	0.00%