Capital Stock - Narratives (Details) - USD ($)			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
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock, shares	805,000	805,000	400,000	313,006	200,000	713,006	2,511,578	1,669,924
Remaining authorized shares for repurchases (shares)					$ 95,200,000		$ 100,000,000
Shares paid for tax withholding for share based compensation					117,426	134,736	161,988	145,395
Value of shares paid for tax withholding for share based compensation					$ 12,600,000	$ 10,800,000	$ 12,600,000	$ 4,700,000
Average Price Per Share (in dollars per share)		$ 74.53	$ 94.77	$ 79.87	$ 84.38	$ 88.23	$ 67.69	$ 52.19
Total Consideration (In thousands)			$ 37,900,000	$ 25,000,000	$ 16,875,000	$ 62,909,000	$ 169,997,000	$ 87,146,000
Shares repurchased value			$ 75,000,000.0			75,000,000.0
Stock Repurchased and Retired During Period, Value	$ 60,000,000	$ 60,000,000			16,875,000	62,909,000	169,997,000	$ 87,146,000
Shares cancelled, value					$ 11,500,000	$ 42,800,000	17,100,000
Notes Offering [Member]
Equity, Class of Treasury Stock [Line Items]
Total Consideration (In thousands)							$ 110,000,000