PARTNERS' CAPITAL - Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands						3 Months Ended	12 Months Ended
Feb. 14, 2020	Nov. 14, 2019	Aug. 14, 2019	May 15, 2019	Feb. 14, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
PARTNERS' CAPITAL
Quarterly distribution paid (in dollars per unit)	$ 0.4000	$ 0.5400	$ 0.5400	$ 0.5350	$ 0.5300	$ 0.4000		$ 2.1450
Total Cash Distribution	$ 51,753	$ 69,772	$ 70,153	$ 69,489	$ 69,011	$ 51,753	$ 69,011	$ 278,425

The distributions of earnings to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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Period Type:	duration