FINANCING ARRANGEMENTS (Schedule of Balances Attributable to Notes) (Details) - USD ($) $ in Thousands	Aug. 31, 2016	Feb. 29, 2016	May 31, 2015
Liability component:
1.625% convertible senior unsecured notes	$ 143,260	$ 139,800
Convertible Senior Notes [Member]
Liability component:
Term loan amount	172,500	172,500
Less: Unamortized debt discount	(25,933)	(29,002)	$ (33,600)
Unamortized debt issuance costs	(3,307)	(3,698)
1.625% convertible senior unsecured notes	$ 143,260	$ 139,800