Revenue and Contract Receivables, net, Allowance for Doubtful Accounts and Contract Adjustments (Details) - USD ($) $ in Thousands		3 Months Ended
		Oct. 29, 2016	Oct. 31, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period		$ 5,929	$ 5,954
Net increase (decrease) due to adjustments in the allowance for contract adjustments	[1]	(46)	(29)
Net increase (decrease) due to adjustments in the allowance for doubtful accounts	[2]	136	(6)
Balance at end of period		$ 6,019	$ 5,919

[1] Increases (decreases) to the allowance for contract adjustments on the condensed consolidated balance sheets are also recorded as (decreases) increases to revenue on the condensed consolidated statements of operations.

[2] Increases (decreases) to the allowance for doubtful accounts on the condensed consolidated balance sheets are also recorded as increases (decreases) to administrative and other indirect operating expenses on the condensed consolidated statements of operations.