XML 49 R36.htm IDEA: XBRL DOCUMENT v3.19.2
Goodwill and Intangible Assets - Summary of Change in Net Carrying Value of Goodwill (Detail) - USD ($)
$ in Millions
9 Months Ended
Jul. 31, 2019
Jul. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]    
Balance at beginning of period $ 161.8 $ 133.2
Acquisitions (2.0) 29.4
Balance at end of period $ 159.8 $ 162.6