v3.19.3.a.u2
UNIT-BASED COMPENSATION Narrative 4 (Details) - Performance Units [Member] - USD ($)
$ in Millions
12 Months Ended
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)