Prior Period Cost Reduction Actions (Details) - USD ($)			12 Months Ended
	Aug. 01, 2019	Aug. 01, 2018	Jul. 31, 2020	Jul. 31, 2019
Restructuring Cost and Reserve [Line Items]
Facility exit costs				$ 1,373,000
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member	us-gaap:AccountingStandardsUpdate201409Member
Operating lease liabilities, current	$ 568,000		$ 8,247,000
Other Current Liabilities
Restructuring Cost and Reserve [Line Items]
Remaining estimated facility exit costs	$ 568,000
Operating Segments | Government Solutions
Restructuring Cost and Reserve [Line Items]
Facility exit costs				1,373,000
Operating Segments | Commercial Solutions
Restructuring Cost and Reserve [Line Items]
Facility exit costs				0
Estimated contract settlement costs			$ 444,000	$ 6,351,000