Income Taxes: Reconciliation of unrecognized tax benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Liability for Uncertain Tax Positions, Noncurrent, Period Start | $ 7.8 | $ 13.7 | $ 11.9 |
| Additions for prior year tax positions | 0.8 | 0.6 | |
| Reductions for prior year tax positions | (0.2) | (8.1) | (0.3) |
| Additions for current year tax positions | 0.7 | 1.6 | 2.1 |
| Liability for Uncertain Tax Positions, Noncurrent, Period End | 9.1 | $ 7.8 | $ 13.7 |
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate | $ 8.8 | ||