Segment Reporting (Details) - Reportable Geographical Components [Member] - USD ($) $ in Thousands		12 Months Ended
		Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		$ 83,095	$ 88,715	$ 85,456
Long-lived assets		4,916	5,901	6,566
South America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	[1]	22,722	38,220	42,569
Long-lived assets		1,178	1,213	1,374
Peru [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		9,700	22,800	19,500
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		5,000	8,000	13,800
Chile [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		7,500	6,500	8,800
Other Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		0	0	402
Long-lived assets		$ 0	$ 0	$ 1

[1] Significant South American revenues included revenues from subsidiaries located in Peru ($9.7 million, $22.8 million and $19.5 million for fiscal years 2016, 2015 and 2014, respectively), Brazil ($5.0 million, $8.0 million and $13.8 million for fiscal years 2016, 2015 and 2014, respectively) and Chile ($7.5 million, $6.5 million and $8.8 million for fiscal years 2016, 2015 and 2014, respectively).