Note 8 - Derivative Instruments (Details Textual) $ in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) Contract	Mar. 31, 2023 USD ($)	Mar. 31, 2024 CAD ($) Contract
Derivative [Line Items]
Maximum Allocation of Forecasted CAD-demonimated Operating Costs	75.00%		75.00%
Forecasted CAD-denominated Operating Costs to be Hedged, Term (Year)	5 years
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	$ 400	$ 900
Gain (Loss) on Components Excluded from Assessment of Foreign Currency Cash Flow Hedge Effectiveness	0	0
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	11,200
Other Comprehensive Income (Loss) [Member]
Derivative [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	2,900
Foreign Exchange Forward [Member]
Derivative [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	3,900
Foreign Exchange Forward [Member] | Casa Berardi [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 35,100
Derivative, Forward Exchange Rate	0.01351		0.01351
Foreign Exchange Forward [Member] | Casa Berardi [Member] | Minimum [Member]
Derivative [Line Items]
Derivative, Forward Exchange Rate	0.01278		0.01278
Foreign Exchange Forward [Member] | Casa Berardi [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, Forward Exchange Rate	0.013665		0.013665
Foreign Exchange Forward [Member] | Keno Hill [Member]
Derivative [Line Items]
Derivative, Notional Amount			$ 19.2
Derivative, Forward Exchange Rate	0.000001354		0.000001354
Foreign Exchange Forward [Member] | Casa Berardi and Keno Hill [Member]
Derivative [Line Items]
Derivative, Notional Amount			$ 299.7
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Casa Berardi [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held, Total | Contract	493		493
Derivative, Notional Amount			$ 370.6
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Casa Berardi and Keno Hill [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 278,600
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	1,900	700
Price Risk Derivative [Member]
Derivative [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	12,500
Unsettled Concentrate Sales Contracts [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net, Total	3,100	900
Price Risk Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	1,900	3,000
Commodity Contract [Member]
Derivative [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral, Total	5,400
Derivative, Fair Value, Obligations Under the Agreements	5,400
Zinc Contract 2022 [Member] | Other Comprehensive Income (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net, Total	$ 17,400	$ 8,500