Capital Stock - Repurchase of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended	12 Months Ended
	Sep. 15, 2015	Sep. 09, 2015	Apr. 29, 2017	Jan. 28, 2017	Jan. 27, 2018	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Stockholders' Equity Note [Abstract]
Repurchase of common stock, shares	805,000	805,000	400,000	313,006	200,000	713,006	2,511,578	1,669,924
Total Consideration (In thousands)			$ 37,900	$ 25,000	$ 16,875	$ 62,909	$ 169,997	$ 87,146
Average Price Per Share (in dollars per share)		$ 74.53	$ 94.77	$ 79.87	$ 84.38	$ 88.23	$ 67.69	$ 52.19