Other Accrued Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2016	Jul. 31, 2015
Other Accrued Liabilities [Line Items]
Allowance for project disallowances	$ 2,243	$ 2,243	$ 2,393	$ 1,819	$ 2,243
Other				1,626	1,688
Total other accrued liabilities				$ 3,445	$ 3,931
Allowance for Project Disallowances [Roll Forward]
Balance at beginning of period	2,243	2,393	2,663
Reduction of reserves recorded in prior fiscal years	(424)	(150)	(300)
Net change during the period, recorded as a transfer of reserves from allowance for doubtful accounts and contract adjustments	0	0	30
Balance at end of period	1,819	2,243	2,393
Maximum [Member]
Allowance for Project Disallowances [Roll Forward]
Reduction of reserves recorded in prior fiscal years	$ 100	$ 100	$ 100