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, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Quarterly Financial Data [Abstract]
Net sales	$ 593.8	$ 571.3	$ 517.2	$ 538.0	$ 610.6	$ 575.6	$ 588.5	$ 596.5					$ 2,220.3	$ 2,371.2	$ 2,473.5
Gross profit	209.3	196.6	170.8	178.1	202.3	194.1	203.1	209.1					754.8	808.6	877.8
Net earnings	$ 59.5	$ 54.8	$ 38.0	$ 38.5	$ 56.4	$ 47.8	$ 48.0	$ 55.9					$ 190.8	$ 208.1	$ 260.2
Basic (in shares)	$ 0.44	$ 0.41	$ 0.28	$ 0.29	$ 0.41	$ 0.35	$ 0.35	$ 0.40					$ 1.43	$ 1.51	$ 1.79
Diluted (in shares)	$ 0.44	$ 0.41	$ 0.28	$ 0.29	0.41	0.34	0.34	0.40					1.42	1.49	1.76
Dividends declared per share (in dollars per share)					0.175	0.175	0.17	0.17	$ 0.34	$ 0	$ 0.33	$ 0	$ 0.690	$ 0.670	$ 0.610
Dividends declared per share, cash paid (in dollars per share)					$ 0.175	$ 0.170	$ 0.17	$ 0.170	$ 0.17	$ 0.165	$ 0.165	$ 0.165