Pension and Defined Contribution Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Amounts Recognized in the Consolidated Balance Sheets Consist of:
Current liabilities	$ (1.6)	$ (1.2)
Non-current liabilities	(83.9)	(65.1)
Domestic Plans
Change in Benefit Obligation:
Benefit obligation at beginning of year	171.5	151.5
Service cost	3.1	2.4	$ 3.4
Interest cost	6.8	7.0	6.3
Amendments	10.5	0.0
Actuarial loss	7.6	17.6
Plan settlements	0.0	0.0
Benefits paid	(7.3)	(7.0)
Other	0.0	0.0
Benefit obligation at end of year	192.2	171.5	151.5
Change in Plan Assets:
Fair value of plan assets at beginning of year	122.5	105.7
Actual return on plan assets	0.7	15.1
Employer contributions	8.0	8.7
Benefits paid	(7.3)	(7.0)
Other	0.0	0.0
Fair value of plan assets at end of year	123.9	122.5	105.7
Funded status at end of year:
Funded status at the end of year	(68.3)	(49.0)
Amounts Recognized in the Consolidated Balance Sheets Consist of:
Current liabilities	(1.5)	(1.2)
Non-current liabilities	(66.8)	(47.8)
Net amount recognized in Consolidated Balance Sheets	(68.3)	(49.0)
Accumulated Benefit Obligation	189.2	170.7
Pre-tax amounts in accumulated other comprehensive income:
Prior service cost	(13.9)	(4.5)
Net actuarial loss	(71.1)	(57.5)
Amounts in accumulated other comprehensive income	(85.0)	(62.0)
Estimated amounts that will be amortized from accumulated comprehensive income over the next fiscal year:
Prior service cost	3.1	0.8
Net actuarial loss	$ 3.1	$ 2.4
Incremental benefit period	180 months
Percentage of participant's annual compensation subject to incremental benefit per the plan amendment	1.40%
Percentage used in defining actuarial equivalent	2.50%	7.00%
Additional percentage point on US Treasury Bond Rate		1.50%
Maximum number of years of credited service subject to incremental benefit	10 years
International Plans
Change in Benefit Obligation:
Benefit obligation at beginning of year	$ 52.5	$ 40.2
Service cost	0.1	0.1	0.1
Interest cost	1.8	1.9	1.7
Amendments	0.0	0.0
Actuarial loss	0.5	8.6
Plan settlements	0.0	(0.1)
Benefits paid	(1.0)	(1.0)
Other	(4.1)	2.8
Benefit obligation at end of year	49.8	52.5	40.2
Change in Plan Assets:
Fair value of plan assets at beginning of year	35.2	30.1
Actual return on plan assets	(0.1)	2.9
Employer contributions	1.1	1.1
Benefits paid	(1.0)	(1.0)
Other	(2.6)	2.1
Fair value of plan assets at end of year	32.6	35.2	$ 30.1
Funded status at end of year:
Funded status at the end of year	(17.2)	(17.3)
Amounts Recognized in the Consolidated Balance Sheets Consist of:
Current liabilities	(0.1)	0.0
Non-current liabilities	(17.1)	(17.3)
Net amount recognized in Consolidated Balance Sheets	(17.2)	(17.3)
Accumulated Benefit Obligation	49.8	52.3
Pre-tax amounts in accumulated other comprehensive income:
Prior service cost	0.0	0.0
Net actuarial loss	(19.4)	(20.5)
Amounts in accumulated other comprehensive income	(19.4)	(20.5)
Estimated amounts that will be amortized from accumulated comprehensive income over the next fiscal year:
Prior service cost	0.0	0.0
Net actuarial loss	$ 2.9	$ 1.9