Property, Plant, and Equipment (Detail) (USD $)				12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2014 Building And Improvement Minimum	Jul. 31, 2014 Building And Improvement Maximum	Jul. 31, 2014 Leasehold and Capital Lease Improvements	Jul. 31, 2014 Manufacturing and Engineering Equipment Minimum	Jul. 31, 2014 Manufacturing and Engineering Equipment Maximum	Jul. 31, 2014 Furniture, Fixtures and Computer Equipment Minimum	Jul. 31, 2014 Furniture, Fixtures and Computer Equipment Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives				35 years	40 years		3 years	7 years	3 years	7 years
Property, plant and equipment estimated useful lives						lesser of useful life or the lease term
Land and land improvements	$ 7,500,000	$ 7,400,000
Building and improvements	85,100,000	83,000,000
Leasehold improvements	9,800,000	10,700,000
Equipment and software	129,200,000	118,900,000
Furniture and fixtures	7,300,000	9,400,000
Property, Plant and Equipment, Gross, Total	238,900,000	229,400,000
Less accumulated depreciation and amortization	(124,700,000)	(118,400,000)
Total property, plant and equipment	$ 114,165,000	$ 110,983,000	$ 96,800,000