Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Quarterly Financial Data [Abstract]
Net sales	$ 660.1	$ 608.2	$ 550.6	$ 553.0	$ 593.8	$ 571.3	$ 517.2	$ 538.0	$ 2,371.9	$ 2,220.3	$ 2,371.2
Gross profit	229.5	211.5	187.9	194.2	209.3	196.6	170.8	178.1	823.1	754.8	808.6
Net earnings	$ 68.2	$ 60.1	$ 46.5	$ 58.0	$ 59.5	$ 54.8	$ 38.0	$ 38.5	$ 232.8	$ 190.8	$ 208.1
Net earnings per share – basic (in dollars per share)	$ 0.52	$ 0.45	$ 0.35	$ 0.43	$ 0.44	$ 0.41	$ 0.28	$ 0.29	$ 1.76	$ 1.43	$ 1.51
Net earnings per share – diluted (in dollars per share)	0.51	0.45	0.35	0.43	0.44	0.41	0.28	0.29	1.74	1.42	1.49
Dividends declared per share (in dollars per share)	0.180	0.175	0.175	0.175	0.175	0.175	0.17	0.17	0.71	0.69	0.67
Dividends paid per share (in dollars per share)	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.170	$ 0.17	$ 0.170	$ 0.700	$ 0.685	$ 0.665