Basis of accounting, Currency translation rates (Detail) |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Mar. 31, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| 1 CHF | ||||||
| Foreign Exchange Rates [Line Items] | ||||||
| Closing exchange rate | 1.24 | 1.25 | 1.26 | 1.24 | 1.26 | 1.26 |
| Average rate | 1.27 | 1.28 | 1.23 | 1.27 | 1.17 | |
| 1 EUR | ||||||
| Foreign Exchange Rates [Line Items] | ||||||
| Closing exchange rate | 1.14 | 1.16 | 1.18 | 1.14 | 1.18 | 1.17 |
| Average rate | 1.16 | 1.17 | 1.15 | 1.17 | 1.10 | |
| 1 GBP | ||||||
| Foreign Exchange Rates [Line Items] | ||||||
| Closing exchange rate | 1.33 | 1.32 | 1.37 | 1.33 | 1.37 | 1.35 |
| Average rate | 1.34 | 1.35 | 1.35 | 1.35 | 1.31 | |
| 100 JPY | ||||||
| Foreign Exchange Rates [Line Items] | ||||||
| Closing exchange rate | 0.61 | 0.63 | 0.69 | 0.61 | 0.69 | 0.64 |
| Average rate | 0.63 | 0.63 | 0.70 | 0.63 | 0.68 | |