Net Income Per Share and Weighted Average Shares (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 29, 2016	Apr. 29, 2016	Jan. 29, 2016	Oct. 30, 2015	Jul. 31, 2015	May 01, 2015	Jan. 30, 2015	Oct. 31, 2014	Jul. 29, 2016	Jul. 31, 2015	Aug. 01, 2014
Net Income Per Share and Weighted Average Shares [Abstract]
Net income per share numerator	$ 51,023	$ 49,169	$ 48,242	$ 40,865	$ 47,399	$ 35,317	$ 47,163	$ 34,024	$ 189,299	$ 163,903	$ 132,128
Net income per share denominator [Abstract]
Basic weighted average shares outstanding (in shares)									23,945,041	23,918,368	23,817,768
Add potential dilution [Abstract]
Stock options, nonvested stock awards and MSU Grants (in shares)									129,232	130,556	148,247
Diluted weighted average shares outstanding (in shares)									24,074,273	24,048,924	23,966,015