Reportable Segments - Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 228,854	$ 217,268	$ 213,034	$ 212,766	$ 205,502	$ 192,113	$ 184,817	$ 187,725	$ 871,922	$ 770,157	$ 664,755
Total long-lived assets:	120,077				93,045				120,077	93,045	79,753
Goodwill and intangible assets, net	505,388				435,957				505,388	435,957	392,037
Total	625,465				529,002				625,465	529,002	471,790
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									643,744	599,657	515,055
Total long-lived assets:	80,918				74,401				80,918	74,401	62,820
Europe/Africa/Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									131,130	95,753	88,355
Total long-lived assets:	35,824				16,209				35,824	16,209	14,863
Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									57,108	40,964	33,374
Total long-lived assets:	2,531				1,381				2,531	1,381	1,607
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									33,524	26,648	20,975
Total long-lived assets:	$ 804				$ 1,054				804	1,054	463
Latin America/South America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									$ 6,416	$ 7,135	$ 6,996