FAIR VALUE MEASUREMENTS - Narrative (Details) $ in Millions	Sep. 30, 2020 USD ($)
Level 2
Financial instruments
Notes payable fair value disclosure	$ 718.0
Discount Rate | Level 3 | Obligations | Minimum
Financial instruments
Contingent consideration liability measurement input	0.001
Discount Rate | Level 3 | Obligations | Maximum
Financial instruments
Contingent consideration liability measurement input	0.085
Discount Rate | Level 3 | Obligations | Weighted Average
Financial instruments
Contingent consideration liability measurement input	0.030
Probability of Milestone Achievement | Level 3 | Obligations | Minimum
Financial instruments
Contingent consideration liability measurement input	0.007
Probability of Milestone Achievement | Level 3 | Obligations | Maximum
Financial instruments
Contingent consideration liability measurement input	0.997
Probability of Milestone Achievement | Level 3 | Obligations | Weighted Average
Financial instruments
Contingent consideration liability measurement input	0.706
Volatility of Future Revenue | Level 3 | Obligations | Minimum
Financial instruments
Contingent consideration liability measurement input	0.370
Volatility of Future Revenue | Level 3 | Obligations | Maximum
Financial instruments
Contingent consideration liability measurement input	0.400
Volatility of Future Revenue | Level 3 | Obligations | Weighted Average
Financial instruments
Contingent consideration liability measurement input	0.389