Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE - Narrative (Details)

v3.20.2
FAIR VALUE - Narrative (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Asset retirement obligations $ 294 $ 470  
Second Lien Notes due 2023 | Estimated Fair Value      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Fair value of senior unsecured notes $ 254,200   $ 434,400