Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Reserve for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance at Beginning of Year	$ 1.9	$ 1.5	$ 1.4
Valuation Allowances and Reserves, Charged to Cost and Expense	0.1	0.8	0.2
Valuation Allowances and Reserves, Charged to Other Accounts	0.0	0.0	0.0
Valuation Allowances and Reserves, Deductions	0.7	0.4	0.1
Valuation Allowances and Reserves, Balance at End of Year	1.3	1.9	1.5
Reserve for estimated product returns, net
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance at Beginning of Year	4.3	1.5	1.3
Valuation Allowances and Reserves, Charged to Cost and Expense	44.7	35.9	24.1
Valuation Allowances and Reserves, Charged to Other Accounts	0.0	0.0	0.0
Valuation Allowances and Reserves, Deductions	42.8	33.1	23.9
Valuation Allowances and Reserves, Balance at End of Year	6.2	4.3	1.5
Reserve for estimated cash discounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance at Beginning of Year	2.7	2.2	1.8
Valuation Allowances and Reserves, Charged to Cost and Expense	21.7	19.5	17.4
Valuation Allowances and Reserves, Charged to Other Accounts	0.0	0.0	0.0
Valuation Allowances and Reserves, Deductions	21.4	19.0	17.0
Valuation Allowances and Reserves, Balance at End of Year	3.0	2.7	2.2
Reserve for estimated other deductions
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance at Beginning of Year	1.3	1.0	0.8
Valuation Allowances and Reserves, Charged to Cost and Expense	9.1	7.4	7.4
Valuation Allowances and Reserves, Charged to Other Accounts	0.0	0.0	0.0
Valuation Allowances and Reserves, Deductions	9.1	7.1	7.2
Valuation Allowances and Reserves, Balance at End of Year	1.3	1.3	1.0
Deferred tax asset valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance at Beginning of Year	13.6	12.4	10.2
Valuation Allowances and Reserves, Charged to Cost and Expense	(0.4)	0.4	1.1
Valuation Allowances and Reserves, Charged to Other Accounts	1.8	0.8	1.1
Valuation Allowances and Reserves, Deductions	0.0	0.0	0.0
Valuation Allowances and Reserves, Balance at End of Year	$ 15.0	$ 13.6	$ 12.4