Balance Sheet Accounts and Supplemental Disclosures, (As Restated for fiscal 2014 and 2013) - Schedule of Other Noncurrent Liabilities (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
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Conditional asset retirement obligations	$ 29.3				$ 24.4
Pension benefits, non-qualified	17.9				19.1
Deferred compensation	11.9				11.1
Deferred revenue	13.9				7.4
Other	21.4				18.6
Other noncurrent liabilities	$ 94.4	$ 97.8	$ 99.7	$ 81.8	$ 80.6	$ 79.3	$ 78.3	$ 76.5