Intangible Assets and Goodwill - Goodwill Rollforward (Details) - USD ($)	9 Months Ended	12 Months Ended
	Apr. 30, 2016	Jul. 31, 2015
Changes in Goodwill
Balance at the beginning of the period	$ 241,951,000	$ 231,647,000
Acquisitions	43,889,000	20,162,000
Foreign currency translation	(1,822,000)	(4,118,000)
Sale of business		(5,740,000)
Balance at the end of the period	284,018,000	241,951,000
Endoscopy
Changes in Goodwill
Balance at the beginning of the period	87,007,000	78,274,000
Acquisitions	39,513,000	11,093,000
Foreign currency translation	(2,020,000)	(2,360,000)
Balance at the end of the period	124,500,000	87,007,000
Water Purification and Filtration
Changes in Goodwill
Balance at the beginning of the period	58,872,000	56,838,000
Acquisitions		2,965,000
Foreign currency translation	198,000	(931,000)
Balance at the end of the period	59,070,000	58,872,000
Healthcare Disposables
Changes in Goodwill
Balance at the beginning of the period	87,939,000	81,835,000
Acquisitions	4,376,000	6,104,000
Balance at the end of the period	92,315,000	87,939,000
Dialysis
Changes in Goodwill
Balance at the beginning of the period	8,133,000	8,133,000
Balance at the end of the period	$ 8,133,000	$ 8,133,000
Percentage of estimated fair value exceeding book value		17.00%
Other.
Changes in Goodwill
Balance at the beginning of the period		$ 6,567,000
Foreign currency translation		(827,000)
Sale of business		$ (5,740,000)