Contract Receivables, net, Allowance for Doubtful Accounts and Contract Adjustments (Details) - USD ($) $ in Thousands		12 Months Ended
		Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period		$ 6,792	$ 6,817	$ 7,371
Net increase (decrease) due to adjustments in the allowance for contract adjustments	[1]	(4,941)	(577)	(263)
Net increase (decrease) due to adjustments in the allowance for doubtful accounts	[2]	274	552	(291)
Balance at end of period		2,125	$ 6,792	$ 6,817
Reversal of allowance for doubtful accounts		4,900
Specific write offs of aged and uncollectable contract receivables		$ 4,900

[1] Increases (decreases) to the allowance for contract adjustments on the consolidated balance sheets are recorded as (decreases) increases to revenue on the consolidated statements of operations. During fiscal year 2017, the Company reversed $4.9 million of allowance related to a specific project in the Middle East, for which a corresponding $4.9 million contract receivable balance was also written off during the period.

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