Capital Stock (Details) (USD $)	0 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Mar. 15, 2012	Apr. 27, 2013	Jan. 26, 2013	Oct. 27, 2012	Apr. 27, 2013	Apr. 28, 2012	Jul. 28, 2012	Jul. 30, 2011
Stockholders' Equity Note [Abstract]
Common stock authorized repurchase amount	$ 40,000,000.0
Number of Shares Repurchased		0	0	1,047,000			597,700	5,389,500
Total Consideration (Dollars in thousands)		15,203,000			15,203,000	10,942,000	12,960,000	64,548,000
Average Price Per Share (in dollars per share)		$ 14.52					$ 21.68	$ 11.98
Remaining authorized repurchase amount					$ 22,800,000