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Contractual rate at which a foreign currency can be purchased or sold.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Nominal mass used to calculate payments on a derivative instrument.

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The number of derivative instruments of a particular group held by the entity.

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Note 11 - Derivative Instruments (Details Textual) $ in Thousands, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) oz $ / oz	Sep. 30, 2019 USD ($)	Sep. 30, 2020 CAD ($) $ / oz	Dec. 31, 2019 USD ($)
Maximum Allocation of Forecasted CAD-demonimated Operating Costs		75.00%		75.00%
Forecasted CAD-denominated Operating Costs to be Hedged, Term (Year)		5 years
Derivative Liability, Current		$ 12,232			$ 6,170
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance		(1,400)
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net		2,800
Gain (Loss) on Components Excluded from Assessment of Foreign Currency Cash Flow Hedge Effectiveness		0
Derivative, Gain (Loss) on Derivative, Net, Total		(4,483)	$ (5,824)
Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance		(3,100)
Foreign Exchange Contract [Member] \| Other Current Assets [Member]
Derivative Asset, Current		500
Foreign Exchange Contract [Member] \| Other Noncurrent Assets [Member]
Derivative Assets, Noncurrent, Total		500
Foreign Exchange Contract [Member] \| Other Current Liabilities [Member]
Derivative Liability, Current		2,000
Foreign Exchange Contract [Member] \| Other Noncurrent Liabilities [Member]
Derivative Liability, Noncurrent		$ 2,100
Foreign Exchange Contract [Member] \| Casa Berardi [Member] \| Designated as Hedging Instrument [Member]
Derivative, Number of Instruments Held, Total		143		143
Derivative, Notional Amount		$ 235,900		$ 310.3
Foreign Exchange Contract [Member] \| Casa Berardi [Member] \| Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative, Forward Exchange Rate		1.2702		1.2702
Foreign Exchange Contract [Member] \| Casa Berardi [Member] \| Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative, Forward Exchange Rate		1.3785		1.3785
Foreign Exchange Contract [Member] \| San Sebastian [Member] \| Designated as Hedging Instrument [Member]
Derivative, Number of Instruments Held, Total		0		0
Silver Contracts [Member]
Derivative, Average Price Risk Option Strike Price (in USD per Ounce) \| $ / oz		16.13		16.13
Derivative, Nonmonetary Notional Amount, Mass (Ounce) \| oz		3,900,000
Gold Contracts [Member]
Derivative, Average Price Risk Option Strike Price (in USD per Ounce) \| $ / oz		1,625		1,625
Derivative, Nonmonetary Notional Amount, Mass (Ounce) \| oz		50,511
Commodity Contract [Member]
Derivative Liability, Current		$ 10,200
Derivative Liability, Noncurrent		45
Derivative Liability, Total		1,800
Derivative Liability, Fair Value, Amount Not Offset Against Collateral, Total		16,200
Derivative, Fair Value, Obligations Under the Agreements		16,200
Unsettled Concentrate Sales Contracts [Member]
Derivative, Gain (Loss) on Derivative, Net, Total		12,900
Forecasted Future Concentrate Contracts [Member]
Derivative, Gain (Loss) on Derivative, Net, Total	$ 6,700	$ 12,800