INCOME TAXES - Valuation Allowance (Details) - USD ($) $ in Millions  | 
12 Months Ended | |
|---|---|---|
Dec. 31, 2020  | 
Dec. 31, 2019  | 
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| INCOME TAXES | ||
| Increase in valuation allowance | $ 4.1 | $ 21.6 | 
| X | ||||||||||
- References No definition available. 
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| X | ||||||||||
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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