Note 11 - Commitments, Contingencies and Obligations (Details Textual) $ in Thousands, $ in Thousands			1 Months Ended			3 Months Ended		9 Months Ended
	Oct. 16, 2024 USD ($)	Aug. 26, 2024 USD ($)	May 31, 2024 CAD ($)	Jul. 31, 2018 USD ($)	Jun. 30, 2011 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Loss Contingencies [Line Items]
Environmental remediation expense						$ 1,542	$ 2,256	$ 3,681	$ 6,411
Lessee, operating lease, liability, to be paid						11,659		11,659
Lease Commitments [Member]
Loss Contingencies [Line Items]
Lessee, operating lease, liability, to be paid						11,700		11,700
Performance Obligation Commitments [Member]
Loss Contingencies [Line Items]
Surety bonds						215,400		215,400
Letters of credit outstanding, amount						6,300		6,300
Greens Creek [Member]
Loss Contingencies [Line Items]
Contractual obligation						21,200		21,200
Greens Creek [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						9,800		9,800
Lucky Friday [Member]
Loss Contingencies [Line Items]
Estimated response costs	$ 299,000
Payments for legal settlements	$ 174,300
Lucky Friday [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						18,800		18,800
Keno Hill [Member] | Notice Of Assessment [Member] | Canada Revenue Agency [Member]
Loss Contingencies [Line Items]
Assessed sales tax			$ 1,973,181
Keno Hill [Member] | Sales and Input Tax Credits [Member] | Canada Revenue Agency [Member]
Loss Contingencies [Line Items]
Assessed sales tax			$ 1,038,834
Keno Hill [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						13,100		13,100
Casa Berardi [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						13,500		13,500
Nevada Operations [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						$ 800		800
Johnny M Mine Area near San Mateo, New Mexico [Member]
Loss Contingencies [Line Items]
Payment of response costs		$ 420,000
Estimated response costs				$ 9,600
Johnny M Mine Area near San Mateo, New Mexico [Member] | Environmental Remediation Past Response Costs [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies, period increase (decrease)		$ 10,100						$ 10,100
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member]
Loss Contingencies [Line Items]
Estimated response costs					$ 4,500
Estimated future response cost					$ 100,000