Concentrations of risks - Customer Concentration Risk (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Revenue from Contract with Customer Benchmark | Largest Customer
Concentration Risk [Line Items]
Concentration risk (as a percent)	15.50%	17.90%
Revenue from Contract with Customer Benchmark | Customer, Second Largest
Concentration Risk [Line Items]
Concentration risk (as a percent)	13.60%	16.80%
Revenue from Contract with Customer Benchmark | Customer, Third Largest
Concentration Risk [Line Items]
Concentration risk (as a percent)	10.40%
Accounts Receivable | Largest Customer
Concentration Risk [Line Items]
Concentration risk (as a percent)	21.10%	29.40%
Accounts Receivable | Customer, Second Largest
Concentration Risk [Line Items]
Concentration risk (as a percent)	15.30%	11.40%
Accounts Receivable | Customer, Third Largest
Concentration Risk [Line Items]
Concentration risk (as a percent)	13.80%
Accounts Receivable | Customer, Fourth Largest
Concentration Risk [Line Items]
Concentration risk (as a percent)	11.80%