XML 41 R31.htm IDEA: XBRL DOCUMENT
v3.25.3

Marketable securities (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Marketable securities |
Schedule of Marketable Securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Cost or | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | amortized | ​ | Unrealized
​ | ​ | Market value | ​ | cost | ​ | gain, net
​ | ​ | (In millions)
December 31, 2024: |  | ​ |  |  | ​ |  |  | ​ |
Current assets | ​ | $ | 1.9 | ​ | $ | 1.9 | ​ | $ | —
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Noncurrent assets | ​ | $ | 5.7 | ​ | $ | 5.7 | ​ | $ | —
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
September 30, 2025: | ​ |  |  | ​ |  |  | ​ |  |
Current assets | ​ | $ | 3.1 | ​ | $ | 3.1 | ​ | $ | —
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Noncurrent assets | ​ | $ | 5.8 | ​ | $ | 5.5 | ​ | $ | .3

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of marketable securities. This may consist of investments in certain debt and equity securities, short-term investments and other assets. + References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration