Other Accrued Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2018	Jul. 31, 2017
Other Accrued Liabilities [Abstract]
Allowance for project disallowances	$ 687	$ 687	$ 1,819	$ 687	$ 687
Other				695	1,287
Total other accrued liabilities				$ 1,382	$ 1,974
Allowance for Project Disallowances [Roll Forward]
Balance at beginning of period	687	1,819	2,243
Reduction of reserves recorded in prior fiscal years	0	(1,132)	(424)
Balance at end of period	$ 687	687	1,819
Maximum [Member]
Allowance for Project Disallowances [Roll Forward]
Reduction of reserves recorded in prior fiscal years		$ 100	$ 100