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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Apr. 30, 2019
Apr. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]        
Amortization expense $ 4.6 $ 4.3 $ 9.3 $ 9.1