Other noncurrent liabilities - Other noncurrent liabilities (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Other noncurrent liabilities | ||
| Accrued development costs | $ 13.4 | $ 16.1 |
| Asset retirement obligations | 15.0 | 14.7 |
| Insurance claims and expenses | 17.9 | 16.1 |
| Operating lease liabilities | $ 16.0 | $ 15.7 |
| Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] | Total | Total |
| Deferred income | $ 2.6 | $ 2.9 |
| Other postretirement benefits | 6.1 | 6.4 |
| Uncertain tax positions | 5.4 | |
| Employee benefits | 4.3 | 4.6 |
| Other | 0.6 | 0.5 |
| Total | $ 81.3 | $ 77.0 |
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- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Indicates line item in statement of financial position that includes noncurrent operating lease liability. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of liability, classified as noncurrent, for retirement benefits, classified as other. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Obligations not otherwise itemized or categorized in the footnotes to the financial statements that are expected to be paid after one year (or the normal operating cycle, if longer), from the balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Accrued development costs noncurrent. No definition available.
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- Definition Noncurrent portion of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. No definition available.
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