Business Segment Information - Long-Lived Assets and Total Assets by Geographic Areas (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 80,742	$ 85,567	$ 90,471
Total assets	435,407	451,114	568,166
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	77,568	81,668	85,934
Total assets	292,007	310,209	430,868
Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	3,174	3,899	4,537
Total assets	$ 143,400	$ 140,905	$ 137,298