Property, Plant, and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Property, Plant and Equipment [Line Items]
Land and improvements	$ 7,000	$ 6,900
Building and improvements	85,000	83,000
Leasehold improvements	10,100	10,000
Equipment and software	142,700	133,700
Furniture and fixtures	7,600	7,100
Demonstration Inventory	3,900
Property, Plant and Equipment, Gross, Total	256,300	240,700
Less accumulated depreciation and amortization	(148,500)	(134,400)
Total property, plant and equipment	$ 107,790	$ 106,299	$ 114,165
Land and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	15 years
Building and Improvement | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	10 years
Building and Improvement | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	35 years
Leasehold and Capital Lease Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	lesser of useful life or the lease term
Equipment and Software | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	3 years
Equipment and Software | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	7 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	5 years
Demonstration Inventory
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives	3 years