| LEASE AGREEMENTS - Rent Expense, Net (Details) - USD ($) $ in Millions | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | |
| LEASE AGREEMENTS | |||
| Rent expense under operating lease | $ 6.3 | $ 6.0 | $ 6.0 | 
| X | ||||||||||
| 
- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. No definition available. 
 | 
| X | ||||||||||
| 
- References No definition available. 
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