Liabilities and Restructuring Charges - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 12,907	$ 894	$ 25,012	$ 2,987
Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	12,900		25,012
Cash payments			18,819
Employee related restructuring liabilities	11,872		11,872		$ 5,679
2016 Restructuring Plans | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 9,600
Minimum | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	32,000		32,000
Maximum | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	$ 34,000		$ 34,000