Property, Plant, and Equipment (Detail) (USD $)			6 Months Ended
	Jan. 31, 2014	Jul. 31, 2013	Jan. 31, 2014 Building And Improvement Minimum	Jan. 31, 2014 Building And Improvement Maximum	Jan. 31, 2014 Leasehold and Capital Lease Improvements	Jan. 31, 2014 Manufacturing and Engineering Equipment Minimum	Jan. 31, 2014 Manufacturing and Engineering Equipment Maximum	Jan. 31, 2014 Furniture, Fixtures and Computer Equipment Minimum	Jan. 31, 2014 Furniture, Fixtures and Computer Equipment Maximum	Jan. 31, 2014 Motor Vehicles Minimum	Jan. 31, 2014 Motor Vehicles Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment estimated useful lives			35 years	40 years		4 years	7 years	3 years	7 years	3 years	5 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	85,200,000	83,000,000
Leasehold and capital lease improvements	10,700,000	10,700,000
Manufacturing and engineering equipment	92,400,000	89,700,000
Furniture, fixtures, and computer equipment	34,500,000	22,900,000
Motor vehicles	2,000,000	2,000,000
Construction in process	4,500,000	13,700,000
Property, Plant and Equipment, Gross, Total	236,800,000	229,400,000
Less accumulated depreciation and amortization	(125,000,000)	(118,400,000)
Total property, plant and equipment, net	$ 111,800,000	$ 110,983,000