Acquisitions (Details 4) (USD $)	0 Months Ended	1 Months Ended
	Jun. 30, 2014 project	Aug. 31, 2014	Apr. 30, 2015	Jul. 31, 2014	Jul. 31, 2013
Net Assets
Goodwill			$ 242,501,000	$ 231,647,000	$ 211,618,000
Puri Core International Limited
Acquisitions
Pre-acquisition annual revenues	25,000,000
Acquisition-related costs	703,000
Total consideration for the transaction, excluding acquisition-related costs	27,675,000
Net asset value adjustment		337,000
Net Assets
Current assets	8,982,000
Property, plant and equipment	972,000
Non-current deferred income tax assets, net	1,924,000
Current liabilities	(10,085,000)
Other long-term liabilities	(753,000)
Net assets acquired	14,233,000
Amortizable intangible assets, useful life	9 years
Number of in-process research and development projects acquired	0
Goodwill	13,442,000
Goodwill deductible for income tax purposes	0
Contingent consideration liability	1,414,000		914,000
Puri Core International Limited | Current liabilities
Net Assets
Contingent consideration liability	693,000		601,000
Puri Core International Limited | Other long-term liabilities
Net Assets
Contingent consideration liability	721,000		313,000
Puri Core International Limited | Customer relationships
Net Assets
Amortizable intangible assets	11,340,000
Amortizable intangible assets, useful life	10 years
Puri Core International Limited | Technology
Net Assets
Amortizable intangible assets	1,760,000
Amortizable intangible assets, useful life	6 years
Puri Core International Limited | Other
Net Assets
Amortizable intangible assets	$ 93,000
Amortizable intangible assets, useful life	3 years