Stock-based compensation and equity transactions - Summary of fair value of employee and non-employee directors' stock options (Detail)	3 Months Ended
	Jan. 31, 2020	Jan. 31, 2019
Stock-based compensation and equity transactions
Risk-free interest rate	1.57%	2.98%
Dividend yield	1.23%	0.94%
Expected life of the option	6 years 5 months 19 days	5 years 9 months 4 days
Volatility factor	49.14%	55.64%