Basis of Presentation and Accounting Policies - Revenue Recognition (Details)	3 Months Ended
Oct. 28, 2017	Oct. 29, 2016
Maximum \| Revenue Recognized Using Cost To Cost Percentage of Completion Method
Revenue from External Customer [Line Items]
Percentage of Revenue	5.00%	5.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration