v3.26.1
Mineral Stream Interests - Schedule of Mineral Stream Interests (Parenthetical) (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Sep. 30, 2025
Jun. 30, 2026
Dec. 31, 2025
Dec. 31, 2024
Disclosure Of Mineral Stream Interests [line items]        
Buy back option percentage exercised 33.00%      
Gold interests [member] | Other gold interests [member] | Cangreios [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       $ 3,000
Gold interests [member] | Other gold interests [member] | Marmato [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   $ 37,000    
Gold interests [member] | Other gold interests [member] | Fenix [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest     $ 125,000  
Gold interests [member] | Other gold interests [member] | Kudz Ze Kayah [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       1,000
Gold interests [member] | Other gold interests [member] | Kurmuk [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       131,000
Gold interests [member] | Other gold interests [member] | El Domo [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       32
Gold interests [member] | Other gold interests [member] | Kone [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   156,000 469,000  
Gold interests [member] | Other gold interests [member] | Hemlo [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest     300,000  
Gold interests [member] | Other gold interests [member] | Spring Valley [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   50,000 50,000  
Gold interests [member] | Other gold interests [member] | Santo Domingo [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Repayments Of Other Than Through Business Combinations Mineral Stream Interests   30,000    
Gold interests [member] | Other gold interests [member] | Jervois [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   6,000    
Silver interests [member] | Other silver interests [member] | Mineral Park [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       40,000
Silver interests [member] | Other silver interests [member] | Marmato [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   3,000    
Silver interests [member] | Other silver interests [member] | Kudz Ze Kayah [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       1,000
Silver interests [member] | Other silver interests [member] | El Domo [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest       $ 12,000
Silver interests [member] | Other silver interests [member] | Jervois [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Additions other than through business combination mineral stream interest   10,000    
Accumulated impairment [member] | Gold interests [member] | Sudbury [member]        
Disclosure Of Mineral Stream Interests [line items]        
Cumulative impairment charges   120,000 120,000  
Accumulated impairment [member] | Silver interests [member] | El Alto [Member]        
Disclosure Of Mineral Stream Interests [line items]        
Cumulative impairment charges   338,000 338,000  
Accumulated impairment [member] | Cobalt Interests [member] | Voisey's Bay [member]        
Disclosure Of Mineral Stream Interests [line items]        
Cumulative impairment charges   $ 109,000 $ 109,000