EARNINGS PER UNIT (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners		$ 25,629	$ (789)	$ 89,386	$ (11,130)
Deemed contribution on exchange of preferred units		$ 54,945		$ 54,945
Phantom Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU		4,031	176	3,353	70
Limited Partner Interest Before Subordinated Units Converted To Common Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners		$ 25,629	$ (789)	$ 89,386	$ (11,130)
Series A Preferred Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners		6,481	7,125	20,731	21,375
Deemed contribution on exchange of preferred units		54,945		54,945
Series A Preferred Units | Subsidiaries
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners		7,298		9,640
Common units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners		$ 66,795	$ (7,914)	$ 113,960	$ (32,505)
Basic (shares)	[1]	51,974,000	45,319,000	47,331,000	45,319,000
Effect of nonvested phantom units		1,676		1,451
Diluted (shares)		53,650,000	45,319,000	48,782,000	45,319,000
Common unit – basic		$ 1.29	$ (0.17)	$ 2.41	$ (0.72)
Common unit – diluted		$ 1.25	$ (0.17)	$ 2.34	$ (0.72)

[1] As a result of the GP Buy-In Transaction, our historical results are those of Summit Investments. The number of common units of 45.3 million as of September 30, 2019 represents those of Summit Investments and has been used for the earnings per unit calculations presented herein.