Information as to Reportable Segments and Foreign and Domestic Operations - Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Net sales
Net sales	$ 205,502	$ 192,113	$ 184,817	$ 187,725	$ 179,002	$ 173,703	$ 158,271	$ 153,779	$ 770,157	$ 664,755	$ 565,004
Total long-lived assets:	93,045				79,753				93,045	79,753	67,883
Goodwill and intangible assets, net	435,957				392,037				435,957	392,037	327,787
Total	529,002				471,790				529,002	471,790	395,670
United States
Net sales
Net sales									599,657	515,055	447,848
Total long-lived assets:	74,401				62,820				74,401	62,820	57,080
Europe/Africa/Middle East
Net sales
Net sales									95,753	88,355	62,193
Total long-lived assets:	16,209				14,863				16,209	14,863	9,122
Asia/Pacific
Net sales
Net sales									40,964	33,374	28,529
Total long-lived assets:	1,381				1,607				1,381	1,607	1,081
Canada
Net sales
Net sales									26,648	20,975	19,306
Total long-lived assets:	$ 1,054				$ 463				1,054	463	600
Latin America/South America
Net sales
Net sales									$ 7,135	$ 6,996	$ 7,128