Segment reporting - Summarized financial information (Details) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
Sep. 30, 2026
USD ($)
|
Sep. 30, 2025
USD ($)
|
Sep. 30, 2026
USD ($)
|
Sep. 30, 2025
USD ($)
|
|
| Disclosure of operating segments [line items] | ||||
| Number of operating segments | 3 | |||
| Revenues from external customers | $ 490.5 | $ 403.9 | $ 1,334.5 | $ 1,184.2 |
| Elimination of intersegment amounts | ||||
| Disclosure of operating segments [line items] | ||||
| Revenues from external customers | 0.0 | |||
| Nigeria | ||||
| Disclosure of operating segments [line items] | ||||
| Revenues from external customers | 359.4 | 268.0 | 942.6 | 799.7 |
| SSA | ||||
| Disclosure of operating segments [line items] | ||||
| Revenues from external customers | $ 131.1 | $ 135.9 | $ 391.9 | $ 384.5 |