Unusual Items - Summary of Unusual Items Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014	Aug. 31, 2014
Unusual items
Legal related matters	$ 0.0	$ 0.1	$ (0.7)	$ 0.1
Loss on debt repurchased	0.5	45.9	0.7	50.8	$ 60.6
Loss on bank amendment	0.0	0.2	0.0	0.2	$ 0.2
Total unusual items	$ 0.5	$ 46.2	$ 0.0	$ 51.1