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Fair Value Measures - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Jul. 31, 2019
Jul. 31, 2018
Jul. 31, 2019
Jul. 31, 2018
Fair Value Disclosures [Abstract]        
Write-down of long-term investments $ 0 $ 0 $ 0 $ 0