Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Nov. 22, 2019	Oct. 31, 2019	Oct. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Number of shares authorized to be repurchased (in shares)		13,000,000.0
Stock repurchased during the period (in shares)		1,400,000
Stock repurchased during the period		$ 65.0	$ 80.9
Shares with remaining authorization for repurchase under stock repurchase plan (in shares)		11,400,000
Dividends paid per share (in usd per share)		$ 0.210	$ 0.190
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Cash dividend declared per common share (in usd per share)	$ 0.210