| CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 
|---|---|---|
| Sep. 30, 2019 | Sep. 30, 2019 | |
| UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS | ||
| Losses accrued on firm purchase commitments | $ 5,000 | $ 5,000 | 
| X | ||||||||||
| 
- Definition Refers to losses accrued on firm purchase commitments. No definition available. 
 | 
| X | ||||||||||
| 
- References No definition available. 
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