MYRTLE GROVE SHARE PURCHASE AND SUBSCRIPTION AGREEMENT - Narrative (Details)	Jul. 26, 2019 USD ($) $ / shares shares	Jul. 25, 2019 USD ($) shares	Sep. 30, 2019 USD ($)
MG SPV | Vertex Operating
Equity, Class of Treasury Stock [Line Items]
Ownership percentage	84.42%
MG SPV | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Ownership percentage by noncontrolling interest	15.58%
Tensile-Heartland
Equity, Class of Treasury Stock [Line Items]
Purchase option, execution and closing period	30 days
Percentage of interests to be acquired	65.00%
Heartland SPV
Equity, Class of Treasury Stock [Line Items]
Percentage of interests to be acquired	35.00%
Cash and cash equivalents	$ 13,500,000
Vertex Refining LA, LLC | MG SPV
Equity, Class of Treasury Stock [Line Items]
Assets acquired		$ 22,666,667
Tensile-MG | MG SPV
Equity, Class of Treasury Stock [Line Items]
Percentage acquired	15.58%
Subscription Agreement | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Number of shares issued | shares	1,500,000
Number of warrants (in shares) | shares	1,500,000
Warrants value	$ 2,220,000
Warrants, price per share (in dollars per share) | $ / shares	$ 1.48
Exercise price (in dollars per share) | $ / shares	$ 2.25
Warrant term	10 years
Beneficial ownership limitation (as a percent)	4.999%
Beneficial ownership limitation, upon 61 days notice (as a percent)	9.999%
Lock-Up Agreement | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Termination of lock-up, period of consecutive trading days that common stock is not traded on Nasdaq		5 days
Lock-up period		1 year
Period of maximum units sold		90 days
Minimum | MG SPV
Equity, Class of Treasury Stock [Line Items]
Indemnification liability	$ 226,000
Maximum | MG SPV
Equity, Class of Treasury Stock [Line Items]
Indemnification liability	3,400,000
Maximum | MG SPV | MG SPV
Equity, Class of Treasury Stock [Line Items]
Indemnification liability	$ 4,000,000
Maximum | Lock-Up Agreement | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Number of shares issued | shares		300,000
Warrant term		4 years
Common Class A | Vertex Refining LA, LLC | MG SPV
Equity, Class of Treasury Stock [Line Items]
Units purchased (in shares) | shares		21,667
Common Class B | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Common units, conversion ratio		1
Percentage of aggregate capital investment to be added to original per-unit price to determine cash purchase price		50.00%
Percentage of voting power of the outstanding voting securities (more than)		50.00%
Common Class B | Vertex Refining LA, LLC | MG SPV
Equity, Class of Treasury Stock [Line Items]
Units purchased (in shares) | shares		1,000
Common Class B | Vertex Operating | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Units sold (in shares) | shares	1,000
Units sold, value	$ 1,000,000
Common Class B | MG SPV | Tensile-MG
Equity, Class of Treasury Stock [Line Items]
Units sold (in shares) | shares	3,000
Units sold, value	$ 3,000,000
Maximum transaction costs	$ 850,000
Restricted cash and cash equivalents			$ 1,900,000