Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jan. 27, 2018	Jan. 28, 2017	Jan. 25, 2020	Jan. 26, 2019	Jul. 29, 2017
Income Tax Disclosure [Abstract]
Statutory rate applied to pre-tax income	$ 15,334		$ 16,495	$ 18,488	$ 87,649
State taxes, net of federal tax benefit	1,406		4,282	4,004	9,868
Tax Reform and related effects	(32,249)		1,093	0	0
Federal benefit of vesting and exercise of share-based awards	(7,067)		875	(200)	0
Non-deductible and non-taxable items, net	1,585		1,433	2,433	(4,686)
Change in accruals for uncertain tax positions	250		891	464	632
Tax credits	(1,596)		(2,801)	(1,835)	0
Change in valuation allowance	0		722	291	0
Effect of rates other than statutory	557		(197)	1,537	6
Other items, net	(505)		(1,472)	(51)	(261)
Total provision for income taxes	$ (22,285)	$ 44,332	$ 21,321	$ 25,131	$ 93,208