CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jan. 27, 2018	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 68,835	$ 157,217	$ 128,740	$ 84,324
Foreign currency translation gains (losses), net of tax	12	116	(76)	(1,040)
Comprehensive income	$ 68,847	$ 157,333	$ 128,664	$ 83,284