Capital Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended	3 Months Ended			6 Months Ended		18 Months Ended
	Sep. 15, 2015	Sep. 11, 2015	Jan. 28, 2017	Apr. 23, 2016	Oct. 24, 2015	Jan. 28, 2017	Jan. 23, 2016	Aug. 31, 2018	Mar. 02, 2017	Feb. 28, 2017
Class of Stock [Line Items]
Number of shares repurchased	805,000		313,006	1,557,354	954,224
Total Consideration (Dollars in thousands)			$ 25,000	$ 100,000	$ 69,997	$ 25,000	$ 69,997
Average Price Per Share (in dollars per share)	$ 74.53		$ 79.87	$ 64.21	$ 73.35
Cumulative Effect on Retained Earnings, Net of Tax			$ 12,100
Stock repurchased and retired during period, value	$ 60,000	$ 110,000
Remaining Authorized Repurchase Amount			$ 75,000			$ 75,000
Shares paid for tax withholding for share based compensation			128,783		156,362
Value of shares paid for tax withholding for share based compensation			$ 10,200		$ 12,100
Subsequent Event [Member]
Class of Stock [Line Items]
Stock Repurchase Program Expiration Date								Aug. 31, 2018
Remaining Authorized Repurchase Amount									$ 150,000
Stock Repurchase Program, Authorized Amount										$ 75,000