DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Fair Value of Derivative Instruments (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Foreign exchange forward contracts, asset	$ 2.7	$ 2.8
Foreign exchange forward contracts, liability	0.0	6.0
Prepaid expenses and other | Not Designated as Hedging Instrument
Derivative [Line Items]
Foreign exchange forward contracts, asset	2.7
Prepaid expenses and other | Designated as Hedging Instrument
Derivative [Line Items]
Foreign exchange forward contracts, asset		2.8
Accounts payable | Not Designated as Hedging Instrument
Derivative [Line Items]
Foreign exchange forward contracts, liability	$ 0.0
Accounts payable | Designated as Hedging Instrument
Derivative [Line Items]
Foreign exchange forward contracts, liability		$ 6.0