EQUITY METHOD INTERESTS - Summarized Financial Information of Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule of Equity Method Investments [Line Items]
Revenues	$ 34,146	$ 40,869	[1]
Operating income (loss)	13,047	18,652	[1]
Net income (loss)	22,489	(25,371)	[1],[2]
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Gulf Coast Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Revenues	88,369	92,205
Operating income (loss)	60,108	65,706
Net income (loss)	59,768	65,658
Other comprehensive income (loss)	0	0
Equity Method Investment, Nonconsolidated Investee or Group of Investees | EPIC Crude Holdings, LP
Schedule of Equity Method Investments [Line Items]
Revenues	33,206	40,759
Operating income (loss)	(8,384)	(5,671)
Net income (loss)	(31,039)	(13,984)
Other comprehensive income (loss)	4,197	(7,887)
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Permian Highway Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Revenues	97,848	0
Operating income (loss)	42,580	(23)
Net income (loss)	42,580	425
Other comprehensive income (loss)	0	0
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Breviloba, LLC
Schedule of Equity Method Investments [Line Items]
Revenues	34,529	42,818
Operating income (loss)	17,300	25,589
Net income (loss)	17,359	22,184
Other comprehensive income (loss)	$ 0	$ 0

[1] This period presented has been revised to reflect the Company’s fair value change of its underlying warrants. Refer to Note 1—Summary of Significant Accounting Policies, see the section titled Revision of Previously Issued Consolidated Financial Statements for Immaterial Adjustment for further information.

[2] This period presented has been revised to reflect the Company’s fair value change of its underlying warrants. Refer to Note 1—Summary of Significant Accounting Policies, see the section titled Revision of Previously Issued Consolidated Financial Statements for Immaterial Adjustment for further information.