Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Oct. 27, 2018	Jul. 31, 2018
Fair Value of Financial Instruments [Abstract]
Investment securities available for sale	$ 1,505	$ 1,497

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant