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Represents the value of warrants entitled during the period.

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The number of issuance installments for a debt instruments.

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Represents the amount of estimated response costs that may be incurred.

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Represents the estimated future response cost that the EPA may ultimately incur related to a site.

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Represents the estimated amount of response costs that have been incurred by the EPA in cleaning up a site.

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Represents the amount of open purchase orders as of a specified date.

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Percentage of ownership in properties.

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Represents the amount of response costs paid during the period.

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Represents the amount of surety bonds in place as of a specified date. Such surety bonds may be for the purpose of, but not limited to, financial support for future reclamation and closure costs, self-insurance, and employee benefit plans.

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No definition available.

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Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

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No definition available.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of lessee's undiscounted obligation for lease payments for finance lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Note 4 - Commitments, Contingencies and Obligations (Details Textual) $ in Thousands, $ in Millions						1 Months Ended					3 Months Ended			9 Months Ended
	Oct. 09, 2020 CAD ($)	Sep. 09, 2020 CAD ($)	Aug. 09, 2020 CAD ($)	Jul. 09, 2020 CAD ($)	Oct. 30, 2019 USD ($)	Oct. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)	Dec. 31, 2014 USD ($)	Aug. 31, 2012 USD ($)	Jun. 30, 2011 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jul. 09, 2020 USD ($)	Jul. 09, 2020 CAD ($)	Feb. 19, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 11, 2018
Environmental Remediation Expense						$ 6,100					$ 1,254	$ 1,907		$ 2,807	$ 3,529
Payments of Debt Issuance Costs														1,287	$ 587
Contractual Obligation, Total											700			700
Finance Lease, Liability, Payment, Due, Total											14,989			14,989
Lessee, Operating Lease, Liability, to be Paid, Total											13,602			13,602
Letters of Credit Outstanding, Amount											20,300			20,300
Performance Obligation Commitments [Member]
Surety Bonds											182,600			182,600
Letters of Credit Outstanding, Amount											20,300			20,300
Lucky Friday [Member]
Open Purchase Orders											3,200			3,200
Casa Berardi [Member]
Open Purchase Orders											400			400
Greens Creek [Member]
Open Purchase Orders											5,600			5,600
Nevada Operations [Member]
Open Purchase Orders											3,300			3,300
Senior Notes [Member] \| The 2028 Senior Notes [Member]
Debt Instrument, Face Amount																		$ 475,000
Debt Instrument, Interest Rate, Stated Percentage																		7.25%
Long-term Debt, Gross											$ 475,000			$ 475,000
Senior Notes [Member] \| The 2021 Senior Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage																			6.875%
Long-term Debt, Gross																			$ 506,500
Senior Notes [Member] \| The IQ Notes [Member]]
Debt Instrument, Face Amount																$ 36,800	$ 50.0
Debt Instrument, Interest Rate, Stated Percentage		6.515%
Debt Instrument, Number of Issuance Installments																4	4
Proceeds from Issuance of Debt		$ 12.5	$ 12.5	$ 12.5
Payments of Debt Issuance Costs		$ 0.6
Senior Notes [Member] \| The IQ Notes [Member]] \| Subsequent Event [Member]
Proceeds from Issuance of Debt	$ 12.5
Canadian Assets of Klondex [Member]
Ownership Percentage																				13.00%
PRP Lawsuit in Mineral County, Colorado [Member]
Loss Contingency, Damages Sought, Value					$ 5,000
Lawsuit filed in Ontario (Canada) Superior Court of Justice [Member] \| Waterton Warrants [Member]
Class of Warrant or Right, Issued During Period, Value							$ 3,700
Class of Warrant or Right, Warrants Entitled, Value							8,900
Johnny M Mine Area near San Mateo, New Mexico [Member]
Payment Of Response Costs								$ 1,100	$ 1,100
Estimated Response Costs							$ 9,600	6,100
Environmental Remediation Expense													$ 5,600
Johnny M Mine Area near San Mateo, New Mexico [Member] \| Minimum [Member]
Estimated Alternative Response Costs								0
Johnny M Mine Area near San Mateo, New Mexico [Member] \| Maximum [Member]
Estimated Alternative Response Costs								$ 221,000
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member]
Estimated Response Costs										$ 4,500
Estimated Future Response Cost										$ 100,000