Business Segment Information - Long-Lived Assets and Total Assets by Geographic Areas (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 81,760	$ 80,742	$ 85,567
Total assets	480,931	435,407	451,114
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	79,281	77,580	81,668
Total assets	284,249	294,337	310,209
Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	2,479	3,162	3,899
Total assets	$ 196,682	$ 141,070	$ 140,905