GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Amortization	$ 62.8	$ 62.8	$ 73.8
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	63.0
Finite-Lived Intangible Assets, Amortization Expense, Year Two	63.0
Finite-Lived Intangible Assets, Amortization Expense, Year Three	61.0
Finite-Lived Intangible Assets, Amortization Expense, Year Four	54.0
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 35.0
Trade name | K.A. Steel Chemicals Inc.
Schedule Of Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Finite-Lived Intangible Asset, Useful Life			1 year
Amortization			$ 10.9