UNITHOLDERS' EQUITY AND PARTNERSHIP DISTRIBUTIONS (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Common units
Units issued (in units)						36,588,023	23,518,652
Units outstanding (in units)	23,518,652	36,588,023		36,588,023		36,588,023	23,518,652
Repayment of debt		$ 15,000,000.0		$ 85,000,000
Capital rollforward
Unitholders' capital, beginning balance (in units)	23,518,652			23,518,652
Unitholders' capital, ending balance (in units)		36,588,023		36,588,023
Cash distributions declared and paid (in dollars per unit)		$ 0.13	$ 0.39	$ 0.17	$ 0.37
Common Units
Common units
Units issued (in units)						36,588,023
Units outstanding (in units)	23,518,652	36,588,023		23,518,652		36,588,023	23,518,652
Capital rollforward
Unitholders' capital, beginning balance (in units)	23,518,652			23,518,652
Common units issued for equity offering (in units)				5,000,000
Conversion of Class B Units (in units)				4,913,559
Common units issued under the LTIP (in units)				946,638
Restricted units used for tax withholding (in units)				(1,018)
Forfeiture of restricted units (in units)				(14,166)
Unitholders' capital, ending balance (in units)		36,588,023		36,588,023
Class B
Common units
Units outstanding (in units)	25,557,606	23,141,181		25,557,606		23,141,181	25,557,606
Capital rollforward
Unitholders' capital, beginning balance (in units)	25,557,606			25,557,606
Conversion of Class B Units (in units)				(4,913,559)
Unitholders' capital, ending balance (in units)		23,141,181		23,141,181
Cash distributions (as a percent)				2.00%
Class B Common Units
Capital rollforward
Additional consideration paid per unit (in dollars per unit)				$ 0.05
Springbok Acquisition | Common Units
Capital rollforward
Units issued to acquisition (in units)				2,224,358
Springbok Acquisition | Class B
Capital rollforward
Units issued to acquisition (in units)				2,497,134
Public Offering
Common units
Units issued (in units)	5,000,000
Proceeds from equity offering	$ 73,600,000
Repayment of debt	$ 70,000,000.0
Underwriters option to purchase additional units
Common units
Units issued (in units)	750,000