PROPERTY, PLANT, AND EQUIPMENT, NET (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	$ 520.6	$ 520.6	$ 493.3
Accumulated depreciation	(281.6)	(281.6)	(278.3)
Property, plant, and equipment, net	239.0	239.0	215.0	$ 200.6
Interest costs capitalized		0.5	0.8	0.8
Write-off of property, plant, and equipment	6.5	0.0	0.0	$ 16.3
Land
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	16.0	16.0	12.0
Leasehold improvements
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	62.9	62.9	59.6
Buildings
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	71.9	71.9	68.9
Office equipment
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	27.2	27.2	19.5
Software
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	71.2	71.2	43.4
Machinery and equipment
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	236.4	236.4	237.2
Construction-in-progress
PROPERTY, PLANT, AND EQUIPMENT
Property, plant and equipment	$ 35.0	$ 35.0	$ 52.7