Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended		9 Months Ended
	May. 25, 2016	Mar. 02, 2016	Jan. 28, 2016	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015	May. 29, 2015
Class of Stock [Line Items]
Number of shares authorized to be repurchased								14,000,000.0
Stock repurchased during the period (in shares)				0		2,070,000
Stock repurchased during the period, value						$ 68.0
Average price per share (in usd per share)						$ 32.85
Shares with remaining authorization for repurchase under stock repurchase plan (in shares)				10,900,000.0		10,900,000.0
Cash dividend declared per common share (in usd per share)			$ 0.175
Dividends paid per share (in usd per share)		$ 0.170		$ 0.170	$ 0.165	$ 0.510	$ 0.495
Subsequent Event
Class of Stock [Line Items]
Cash dividend declared per common share (in usd per share)	$ 0.170