Stock-based compensation - Fair Value Assumptions of Stock Options (Detail) - Stock Options	6 Months Ended
	Apr. 30, 2024	Apr. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	30.50%	30.40%
Expected volatility, maximum	31.70%	31.80%
Risk-free interest rate, minimum	4.22%	3.79%
Risk-free interest rate, maximum	4.26%	4.21%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	1.15%	1.12%
Expected life of the option (in years)	5 years	5 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	1.15%	1.27%
Expected life of the option (in years)	6 years 2 months 12 days	6 years 2 months 12 days