Summary of significant accounting policies - Useful Life of Intangible Assets (Details)	Jul. 31, 2024
Customer relationships intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	7 years
Trade name intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	3 years
Software
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	3 years
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	3 years
Minimum | Customer relationships intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	4 years
Minimum | Trade name intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	1 year
Minimum | Software
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	3 years
Minimum | Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	1 year
Maximum | Customer relationships intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	15 years
Maximum | Trade name intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	15 years
Maximum | Software
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	5 years
Maximum | Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life (years)	5 years