v3.20.4
SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 1 (Details) - USD ($)
$ / shares in Units, $ in Thousands
9 Months Ended 12 Months Ended
Jul. 13, 2018
Jun. 29, 2018
Sep. 30, 2018
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Class of Stock [Line Items]            
Proceeds from issuance of Series D preferred units       $ 0 $ 0 $ 590,000
Series D preferred units outstanding       23,246,650 23,246,650  
Series D Preferred Limited Partner [Member]            
Class of Stock [Line Items]            
Proceeds from issuance of Series D preferred units $ 190,000 $ 400,000 $ 590,000      
Series D preferred units outstanding     23,246,650      
Units issued, price per unit $ 25.38 $ 25.38        
Issuance of preferred units (temporary equity) (in units) 7,486,209 15,760,441        
Net proceeds from issuance of Series D preferred units   $ 370,700 $ 555,800     $ 555,797
Transaction fee percentage     3.50%      
Transaction fee     $ 20,700      
Equity issuance costs     $ 13,500