Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 27, 2018	Jul. 29, 2017	Jul. 30, 2016
Deferred tax assets:
Insurance and other reserves	$ 22,368	$ 36,955	$ 33,847
Allowance for doubtful accounts and reserves	1,081	1,975	1,013
Net operating loss carryforwards	822	765	1,151
Stock-based compensation	3,405	8,022	6,424
Other	1,174	1,750	1,363
Total deferred tax assets	28,850	49,467	43,798
Valuation allowance	(148)	(122)	(358)
Deferred tax assets, net of valuation allowance	28,702	49,345	43,440
Deferred tax liabilities:
Property and equipment	59,933	87,581	63,926
Goodwill and intangibles	25,852	38,125	32,632
Other	345	741	736
Deferred tax liabilities	86,130	126,447	97,294
Net deferred tax liabilities	$ 57,428	$ 77,102	$ 53,854