INVENTORIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Oct. 05, 2015
Inventory Disclosure [Abstract]
Supplies	$ 39.2	$ 86.5
Raw materials	63.3	91.5
Work in process	31.8	105.8
Finished goods	141.5	445.3
Inventory, Gross	275.8	729.1
LIFO reserves	(65.7)	(43.9)
Inventories	$ 210.1	$ 685.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory			$ 477.1
Percentage of inventory using the last-in, first-out (LIFO) method of inventory accounting (in hundredths)	58.00%	49.00%
Effect of LIFO Inventory Liquidation on Income	$ 1.5