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