Share-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 27, 2018	Apr. 28, 2017	Apr. 27, 2018	Apr. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 1,742	$ 2,336	$ 6,063	$ 6,347
Nonvested Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	1,495	1,947	5,414	5,045
Performance-Based Market Stock Units ("MSU Grants") [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 247	$ 389	$ 649	$ 1,302