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Special Charge (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Special Charge (Details) - USD ($) $ in Millions	May 31, 2019	May 31, 2018	May 31, 2019	May 31, 2018
Restructuring Cost and Reserve [Line Items]
Special charge	$ (0.1)	$ 9.9	$ 1.3	$ 10.7
Restructuring Reserve [Roll Forward]
Balance, beginning of period			10.1
Severance costs			(0.8)
Payments made during the period			(5.4)
Balance, end of period	3.9		3.9
Fiscal 2018 Actions
Restructuring Reserve [Roll Forward]
Balance, beginning of period			9.2
Severance costs			(0.4)
Payments made during the period			(4.9)
Balance, end of period	3.9		3.9
Fiscal 2017 Actions
Restructuring Reserve [Roll Forward]
Balance, beginning of period			0.9
Severance costs			(0.4)
Payments made during the period			(0.5)
Balance, end of period	0.0		0.0
Severance and employee-related costs
Restructuring Cost and Reserve [Line Items]
Special charge	0.0	9.9	(0.8)	10.5
Move and other restructuring costs
Restructuring Cost and Reserve [Line Items]
Special charge	$ (0.1)	$ 0.0	$ 2.1	$ 0.2