Net Income Per Share and Weighted Average Shares (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 29, 2016	Jan. 30, 2015	Jan. 29, 2016	Jan. 30, 2015
Net Income Per Share and Weighted Average Shares [Abstract]
Net income per share numerator	$ 48,242	$ 47,163	$ 89,107	$ 81,187
Net income per share denominator [Abstract]
Weighted average shares (in shares)	23,937,812	23,914,797	23,947,183	23,888,496
Add potential dilution [Abstract]
Stock options, nonvested stock awards and MSU Grants (in shares)	109,230	117,592	112,864	128,417
Diluted weighted average shares (in shares)	24,047,042	24,032,389	24,060,047	24,016,913