UNIT-BASED COMPENSATION Narrative 4 (Details) - USD ($) |
12 Months Ended | |||
|---|---|---|---|---|
Feb. 01, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Performance Units [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Total fair value of restricted units that vested during the period | $ 4,200,000 | $ 2,100,000 | ||
| Units issued to satisfy award vestings, net of tax (units) | 93,440 | 50,054 | ||
| Unit-based awards, vested (units) | (147,390) | (80,690) | 0 | |
| Performance cash awards | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Performance cash awards granted, amount | $ 2,200,000 | |||
| Performance cash awards | Subsequent Event [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Units issued in connection with performance cash awards | 58,070 | |||