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DERIVATIVE INSTRUMENTS - Activity and Location of Outstanding Derivatives (Details) € in Millions, $ in Millions		12 Months Ended
	Jul. 01, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 EUR (€)	Jul. 31, 2019
Activity related to company's outstanding derivative contracts and location
Gains (losses) related to foreign exchange hedges designated as effective		$ 0.1	$ (0.1)	$ (0.5)
Ineffectiveness recorded				(0.1)
Gains on net investment hedge		4.9	29.6	(46.1)
Amount expected to be reclassified in the coming 12 months		0.1
Senior Notes Due 2023
Activity related to company's outstanding derivative contracts and location
Principal amount of debt \| €					€ 300.0
Interest Rate (as a percent)					5.25%	5.25%
Senior Notes Due March 2022
Activity related to company's outstanding derivative contracts and location
Principal amount of debt \| €					€ 400.0
Interest Rate (as a percent)					4.50%	4.50%
Cost of operations
Activity related to company's outstanding derivative contracts and location
Reclassifications out of accumulated other comprehensive income (loss) into net income		(0.1)	0.2	0.2
Net investment hedge
Activity related to company's outstanding derivative contracts and location
Ineffectiveness recorded		0.0	0.0	0.0
Gains on net investment hedge		4.9	29.6	46.1
Unamortized amount of nest investment hedge	$ (7.5)
Net investment hedge \| Senior Notes Due March 2022
Activity related to company's outstanding derivative contracts and location
Hedged amount \| €					€ 340.0
Foreign currency exchange forward contracts \| General and administrative
Activity related to company's outstanding derivative contracts and location
Gains (losses) on derivative instruments		$ (1.4)	$ 10.6	$ 12.5