FINANCING ARRANGEMENTS - Note Hedges and Warrants (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	12 Months Ended
	May 09, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016
Debt Disclosure [Abstract]
Cost of convertible note hedges		$ 59.1
Number of shares available to be purchased (in shares)	46.3
Strike price (in usd per share)	$ 5.40
Cash proceeds from issuance of warrants				$ 35.5
Incremental common shares attributable to dilutive effect			46.3
Exercise price (in usd per share)			$ 8.50		$ 8.50