Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Quarterly Financial Data [Abstract]
Net sales	$ 617.4	$ 629.7	$ 662.0	$ 672.7	$ 726.9	$ 712.8	$ 703.7	$ 701.4	$ 2,581.8	$ 2,844.9	$ 2,734.2
Gross profit	207.9	209.2	223.2	231.3	243.8	240.7	225.4	238.4	871.6	948.3	935.8
Net earnings	$ 64.2	$ 63.4	$ 64.4	$ 65.0	$ 58.0	$ 75.2	$ 60.1	$ 73.8	$ 257.0	$ 267.2	$ 180.3
Net earnings (loss) per share – basic (in dollars per share)	$ 0.51	$ 0.50	$ 0.51	$ 0.51	$ 0.45	$ 0.59	$ 0.47	$ 0.57	$ 2.03	$ 2.08	$ 1.38
Net earnings (loss) per share – diluted (in dollars per share)	0.50	0.50	0.50	0.51	0.45	0.58	0.46	0.56	2.00	2.05	$ 1.36
Dividends paid per share (in dollars per share)	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.19	$ 0.19	$ 0.19	$ 0.840	$ 0.780