Acquisitions - Sterilator (Details)	Jan. 07, 2014 USD ($) employee	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2014 USD ($)
Net Assets
Goodwill		$ 280,318,000	$ 241,951,000	$ 231,647,000
Sterilator Company, Inc.
Acquisitions
Total consideration for the transaction, excluding transaction costs	$ 3,349,000
Net Assets
Current assets	1,058,000
Property, plant and equipment	521,000
Current liabilities	(321,000)
Deferred income tax liabilities	(276,000)
Net assets acquired	$ 1,622,000
Amortizable intangible assets, useful life	9 years
Number of in-process research and development projects acquired | employee	0
Goodwill	$ 1,727,000
Goodwill deductible for income tax purposes	0
Sterilator Company, Inc. | Customer relationships
Net Assets
Amortizable intangible assets	$ 130,000
Amortizable intangible assets, useful life	11 years
Sterilator Company, Inc. | Technology
Net Assets
Amortizable intangible assets	$ 510,000
Amortizable intangible assets, useful life	8 years