v3.19.3.a.u2

UNIT-BASED COMPENSATION Narrative 4 (Details) - Performance Units [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Units issued to satisfy award vestings, net of tax (units) | 50,054 |  | 33,438
Total fair value of restricted units that vested during the period | $ 2.1 |  | $ 2.9
Unit-based awards, vested (units) | (80,690) | 0 | (53,063)

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