FINANCING ARRANGEMENTS (Summary of Liability and Equity Components of Notes, Issuance Costs and Applicable Assumptions Used for Calculation) (Details) $ / shares in Units, $ in Millions	1 Months Ended	6 Months Ended
	Jul. 31, 2018	Aug. 31, 2019 USD ($) $ / shares	Jul. 20, 2018 USD ($)
2020 Convertible Notes [Member]
Debt Instrument [Line Items]
Initial conversion rate (shares per $1,000 principal amount)		36.2398
Initial conversion price per share | $ / shares		$ 27.5940
Fair value of liability component upon issuance		$ 138.9
Discount Rate		0.0620
Debt Instrument, Measurement Input [Extensible List]		us-gaap:MeasurementInputDiscountRateMember
Fair value measurement level		Level 3
Fair value of embedded equity component upon issuance		$ 33.6
Deferred tax asset effect		16.0
Total issuance cost		4.3
Equity component		1.0
Deferred tax asset effect		0.4
Fair value of convertible notes as of August 31, 2019 (Level 2 measurement)		$ 120.5	$ 47.6
2025 Convertible Notes [Member]
Debt Instrument [Line Items]
Initial conversion rate (shares per $1,000 principal amount)	41.3875	32.5256
Initial conversion price per share | $ / shares		$ 30.7450
Fair value of liability component upon issuance		$ 160.8
Discount Rate		0.0756
Debt Instrument, Measurement Input [Extensible List]		us-gaap:MeasurementInputDiscountRateMember
Fair value measurement level		Level 3
Fair value of embedded equity component upon issuance		$ 69.2
Deferred tax asset effect		17.3
Total issuance cost		7.3
Equity component		2.2
Deferred tax asset effect		0.5
Fair value of convertible notes as of August 31, 2019 (Level 2 measurement)		$ 183.1