Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jul. 31, 2018	Jul. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 8.3	$ 8.7
Preferred stock, par value (in dollars per share)	$ 1	$ 1.00
Preferred stock, share authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 5	$ 5.00
Common stock, shares authorized (in shares)	240,000,000	240,000,000
Common stock, shares issued (in shares)	151,643,194	151,643,194
Treasury stock, shares (in shares)	22,871,145	21,037,353