Comprehensive Income (Changes in Components of Accumulated Other Comprehensive Loss Items) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at August 31, 2014			$ (71.9)
Other Comprehensive Income (Expense), net of tax	$ (0.6)	$ 2.5	(16.9)	$ 4.7
Balance at May 31, 2015	(88.8)		(88.8)
Accumulated Other Comprehensive Loss Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at August 31, 2014			(71.9)
Other Comprehensive Income (Expense) before reclassifications			(18.5)
Amounts reclassified from accumulated other comprehensive income			1.6
Other Comprehensive Income (Expense), net of tax			(16.9)
Balance at May 31, 2015	(88.8)		(88.8)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at August 31, 2014			(18.1)
Other Comprehensive Income (Expense) before reclassifications			(18.5)
Amounts reclassified from accumulated other comprehensive income			0.0
Other Comprehensive Income (Expense), net of tax			(18.5)
Balance at May 31, 2015	(36.6)		(36.6)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at August 31, 2014			(53.8)
Other Comprehensive Income (Expense) before reclassifications			0.0
Amounts reclassified from accumulated other comprehensive income			1.6
Other Comprehensive Income (Expense), net of tax			1.6
Balance at May 31, 2015	$ (52.2)		$ (52.2)