Capital Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended	3 Months Ended				9 Months Ended
	Sep. 15, 2015	Sep. 11, 2015	Apr. 29, 2017	Jan. 28, 2017	Apr. 23, 2016	Oct. 24, 2015	Apr. 29, 2017	Apr. 23, 2016	Jul. 30, 2016
Class of Stock [Line Items]
Number of shares repurchased	805,000		400,000	313,006	1,557,354	954,224
Total Consideration (Dollars in thousands)			$ 37,909	$ 25,000	$ 100,000	$ 69,997	$ 62,909	$ 169,997
Average Price Per Share (in dollars per share)	$ 74.53		$ 94.77	$ 79.87	$ 64.21	$ 73.35
Stock repurchased and retired during period, value	$ 60,000	$ 110,000
Remaining Authorized Repurchase Amount			$ 112,100				$ 112,100		$ 100,000
Cumulative Effect on Retained Earnings, Net of Tax			42,800
Shares paid for tax withholding for share based compensation							130,922	156,362
Value of shares paid for tax withholding for share based compensation							$ 10,400	$ 12,100
Stock Repurchase Program Expiration Date							Aug. 31, 2018
April 2016 Authorization Extension [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount			75,000				$ 75,000
February 2017 Authorization [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount			$ 75,000				$ 75,000