v3.25.2

Long-term debt (Narrative) (Details) - Revolving credit facility [Member] $ in Millions, $ in Millions | Dec. 31, 2025 USD ($) | Dec. 31, 2024 CAD ($)
--- | --- | ---
Disclosure of detailed information about borrowings [line items] |  |
Revolving credit facility, available balance | $ 650 | $ 550
Accordion feature | $ 200 | $ 200

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Accordion feature. + References No definition available. + Details
Name: | or_AccordionFeature
Namespace Prefix: | or_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | or_RevolvingCreditFacilityAvailableBalance
Namespace Prefix: | or_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=or_LineOfCreditsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |