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Commitments and Contingencies - Narrative (Details) $ in Thousands, $ in Millions	Dec. 30, 2013 CAD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 CAD ($)	Dec. 10, 2021 USD ($)
Leases [Line Items]
Equipment purchase commitments		$ 6,900	$ 1,500
Contingent consideration		3,501	3,389	$ 3,404
HudBay Michigan Inc
Leases [Line Items]
Percentage of voting equity interests acquired	100.00%
Back Forty Project
Leases [Line Items]
Contingent consideration due upon project financing intended to pay					$ 3
Aquila Resources Inc. | Gold and silver streaming agreement with OBL | Back Forty Project
Leases [Line Items]
Deposit amount						$ 37,200
Aquila Resources Inc. | Back Forty Project
Leases [Line Items]
Percentage of ownership interest held	100.00%
Contingent consideration	$ 9	$ 3,500
Contingent consideration due upon project financing	$ 3
Percentage of contingent consideration payable in shares	50.00%
Contingent consideration payable in shares	$ 3
Contingent consideration			$ 3,400
Aquila Resources Inc. | Back Forty Project | 90 days after the commencement of commercial production
Leases [Line Items]
Contingent consideration payable in cash	2
Aquila Resources Inc. | Back Forty Project | 270 days after the commencement of commercial production
Leases [Line Items]
Contingent consideration payable in cash	2
Aquila Resources Inc. | Back Forty Project | 450 days after the commencement of commercial production
Leases [Line Items]
Contingent consideration payable in cash	$ 2
HudBay Michigan Inc | HudBay Michigan Inc
Leases [Line Items]
Percentage of net smelter return royalty on production	1.00%
HudBay Michigan Inc | Back Forty Project
Leases [Line Items]
Percentage of voting equity interests acquired at the asset acquisition date tied to the development of project	51.00%
Percentage of ownership purchase to be prevented				51.00%	51.00%

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- Definition

Percentage of voting equity interests acquired at the asset acquisition date tied to the development of project.

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Percentage of voting equity interests acquired at the acquisition date in the asset acquisition.

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The amount contingent consideration due upon project financing.

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The amount contingent consideration due upon project financing intended to pay.

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Amount of contingent consideration payable in cash.

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Amount of contingent consideration payable in shares.

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Leases [Line Items]

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Percentage of contingent consideration payable in shares.

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- Definition

Percentage of net smelter return royalty on production from certain land parcels in the project.

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Percentage of ownership interest held in the project.

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Percentage of ownership purchase to be prevented.

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Amount of liability recognized from contingent consideration in asset acquisition.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480123/805-50-15-3

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Amount of liability recognized from contingent consideration in asset acquisition, classified as noncurrent.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480123/805-50-15-3

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Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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