v3.26.1
Note 10 - Fair Value Measurement - Assets and Liabilities Accounted for at Fair Value (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Receivables from provisional concentrate sales $ 26,615 $ 12,019
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Money market funds and other bank deposits 587,550 241,558
Equity securities 178,049 107,486
Certificates of deposit and other deposits 1,172 1,174
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Receivables from provisional concentrate sales 215,534 170,230
Foreign exchange contracts 384 1,127
Metal forward contracts 16,363 15,840
Foreign exchange contracts 1,318 829
Metal forward contracts $ 15,230 $ 38,273
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Liabilities Liabilities
Fair Value, Inputs, Level 2 [Member] | Gold | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Metal forward contracts $ 3,254 $ 0