Business Segment Information (Details 3) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 87,374	$ 91,316	$ 81,760
Total assets	469,658	485,682	480,931
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	83,401	87,497	77,173
Total assets	258,896	278,676	281,510
Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	3,973	3,819	4,587
Total assets	$ 210,762	$ 207,006	$ 199,421