UNIT-BASED COMPENSATION - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020 USD ($) shares	Sep. 30, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common units reserved for issuance (in shares) \| shares	14,856,026	14,856,026
Unit-based compensation expenses	$ 2.2	$ 6.6
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value		8.6
Unrecognized compensation cost related to unvested phantom units	$ 31.0	$ 31.0
Unrecognized compensation cost related to unvested phantom units, period for recognition		3 years 6 months 21 days

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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