Liabilities and Restructuring Charges - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016	Oct. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 6,026,000	$ 0	$ 31,038,000	$ 2,987,000
Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6,000,000		31,038,000
Cash payments	2,700,000		21,523,000
Employee related restructuring liabilities	15,194,000		15,194,000		$ 5,679,000
2016 Restructuring Plans | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 9,600,000
Employee related restructuring liabilities	$ 0		$ 0