Operating Segments (Details 2) (USD $)	3 Months Ended
	Oct. 31, 2013	Oct. 31, 2012
Information as to operating segments
Net sales	$ 118,272,000	$ 99,681,000
Operating income:	18,312,000	15,972,000
Interest expense, net	(644,000)	(633,000)
Income before income taxes	17,668,000	15,339,000
Operating Segments
Information as to operating segments
Operating income:	21,729,000	18,783,000
Endoscopy
Information as to operating segments
Net sales	43,613,000	36,679,000
Operating income:	8,184,000	7,676,000
Water Purification and Filtration
Information as to operating segments
Net sales	39,750,000	33,161,000
Operating income:	6,057,000	4,627,000
Healthcare Disposables
Information as to operating segments
Net sales	26,249,000	19,955,000
Operating income:	5,719,000	4,091,000
Dialysis
Information as to operating segments
Net sales	7,309,000	8,187,000
Operating income:	1,764,000	2,176,000
Other
Information as to operating segments
Net sales	1,351,000	1,699,000
Operating income:	5,000	213,000
General corporate
Information as to operating segments
General corporate expenses	$ (3,417,000)	$ (2,811,000)