Reportable Segments (Details 1) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Geographical information [Line Items]
Net sales	$ 2,021.5	$ 1,923.6	$ 3,924.0	$ 3,672.5
UNITED STATES
Geographical information [Line Items]
Net sales	1,873.2	1,771.8	3,645.5	3,389.1
CANADA
Geographical information [Line Items]
Net sales	114.3	116.0	212.5	212.9
All Other International [Member]
Geographical information [Line Items]
Net sales	34.0	35.8	66.0	70.5
International [Member]
Geographical information [Line Items]
Net sales	$ 148.3	$ 151.8	$ 278.5	$ 283.4