Long-Term Debt - Summary of Long-term Debt (Details) - USD ($) $ in Millions	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014
Debt Disclosure [Abstract]
Senior debt	$ 93.8				$ 98.8
Senior secured notes	460.0	$ 460.0	$ 460.0	$ 460.0	460.0	$ 460.0	$ 460.0	$ 460.0
Convertible subordinated notes	84.8				133.8
Other debt	13.4				89.6
Total debt, carrying amount	652.0				782.2
Less: Amounts due within one year	(5.3)	$ (5.3)	$ (5.3)	$ (5.3)	(5.3)	$ (5.5)	$ (4.2)	$ (3.0)
Total long-term debt	$ 646.7				$ 776.9