FINANCING ARRANGEMENTS AND CONTRACTUAL CASH OBLIGATIONS (Schedule of Balances Attributable to Notes) (Details) - USD ($) $ in Thousands	Feb. 28, 2017	Feb. 29, 2016	May 31, 2015
Liability component:
1.625% convertible senior unsecured notes	$ 146,827	$ 139,800
Convertible Senior Notes [Member]
Liability component:
Term loan amount	172,500	172,500	$ 172,500
Less: Unamortized debt discount	(22,770)	(29,002)	(33,600)
Unamortized debt issuance costs	(2,903)	(3,698)	$ 5,300
1.625% convertible senior unsecured notes	$ 146,827	$ 139,800