Information as to Operating Segments and Foreign and Domestic Operations - Geographic Areas (Details) - USD ($)	3 Months Ended								12 Months Ended
	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Net sales
Net sales	$ 179,002,000	$ 173,703,000	$ 158,271,000	$ 153,779,000	$ 151,255,000	$ 141,508,000	$ 135,430,000	$ 136,811,000	$ 664,755,000	$ 565,004,000	$ 488,749,000
Total long-lived assets	79,753,000				67,883,000				79,753,000	67,883,000	57,637,000
Goodwill and intangible assets, net	392,037,000				327,787,000				392,037,000	327,787,000	314,599,000
Total	471,790,000				395,670,000				471,790,000	395,670,000	372,236,000
United States
Net sales
Net sales									515,055,000	447,848,000	403,892,000
Total long-lived assets	62,820,000				57,080,000				62,820,000	57,080,000	53,221,000
Europe/Africa/Middle East
Net sales
Net sales									88,355,000	62,193,000	32,634,000
Europe
Net sales
Total long-lived assets	14,863,000				9,122,000				14,863,000	9,122,000	2,275,000
Asia/Pacific
Net sales
Net sales									33,374,000	28,529,000	24,736,000
Total long-lived assets	1,607,000				1,081,000				1,607,000	1,081,000	1,112,000
Canada
Net sales
Net sales									20,975,000	19,306,000	20,729,000
Total long-lived assets	$ 463,000				$ 600,000				463,000	600,000	1,029,000
Latin America/South America
Net sales
Net sales									$ 6,996,000	$ 7,128,000	$ 6,758,000