SEGMENT INFORMATION - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Segment Reporting [Abstract]
Income before income taxes and equity method investment income	$ 6,659	$ 438
Add:
Corporate and Other expense	7,796	12,077
Interest expense	13,953	23,828
Depreciation and amortization	28,746	29,900
Proportional adjusted EBITDA for equity method investees	6,872	7,939
Adjustments related to MVC shortfall payments		(5,442)
Adjustments related to capital reimbursement activity	(1,245)	(211)
Unit-based and noncash compensation	1,967	2,723
(Gain) loss on asset sales, net	(136)	115
Long-lived asset impairment	1,492	3,821
Total of reportable segments' measures of profit	$ 66,104	$ 75,188

Adjusted earnings before interest, taxes, depreciation, and amortization.

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Adjusted earnings before interest, taxes, depreciation, and amortization, proportional equity method investment adjustment.

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- Definition

Adjustments related to capital reimbursement activity.

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Adjustments related to minimum volume commitments shortfall payments.

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Corporate and other expenses.

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Depreciation depletion and amortization including amortization of above and below market leases.

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Reconciliation of net Income to EBITDA, additions.

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- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of noncash expense for share-based payment arrangement.

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