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, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Class of Stock [Line Items] | ||||||
| Proceeds from issuance of Series D preferred units | $ 0 | $ 590,000 | $ 0 | |||
| Series D preferred units outstanding | 23,246,650 | 23,246,650 | ||||
| Net proceeds from issuance of Series D preferred units | $ 555,797 | |||||
| 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 | |||||