Liabilities and Restructuring Charges - Additional Information (Details) - USD ($) |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
---|---|---|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2017 |
Apr. 30, 2018 |
Apr. 30, 2017 |
Oct. 31, 2017 |
|
Restructuring Cost and Reserve [Line Items] | |||||
Restructuring charges | $ 2,176,000 | $ 12,907,000 | $ 1,894,000 | $ 25,012,000 | |
Employee Severance and Benefits | |||||
Restructuring Cost and Reserve [Line Items] | |||||
Restructuring charges | 1,800,000 | $ 36,600,000 | |||
Cash payments | 9,400,000 | 17,300,000 | |||
Employee related restructuring liabilities | 900,000 | 900,000 | $ 17,500,000.0 | ||
Minimum | Employee Severance and Benefits | |||||
Restructuring Cost and Reserve [Line Items] | |||||
Restructuring and Related Cost, Expected Cost | 8,000,000 | 8,000,000 | |||
Maximum | Employee Severance and Benefits | |||||
Restructuring Cost and Reserve [Line Items] | |||||
Restructuring and Related Cost, Expected Cost | $ 10,000,000 | $ 10,000,000 |