SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Recently Adopted Accounting Pronouncements | |||
| Gain/ (losses) on mark-to-market | $ (0.4) | $ 1.2 | $ (1.3) |
| Operating lease liabilities | 113.2 | ||
| ASU 2016-02 | |||
| Recently Adopted Accounting Pronouncements | |||
| Operating lease right-of-use assets | 110.4 | ||
| Operating lease liabilities | $ 113.2 | ||