Note 10 - Commitments, Contingencies and Obligations (Details Textual) - USD ($)			1 Months Ended			3 Months Ended			6 Months Ended
	Jul. 12, 2022	Jun. 30, 2022	Jul. 31, 2018	Aug. 31, 2012	Jun. 30, 2011	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Environmental Remediation Expense						$ 1,472,000	$ 1,024,000		$ 2,373,000	$ 4,733,000
Finance Lease, Liability, to be Paid, Total		$ 15,927,000				15,927,000			15,927,000
Lessee, Operating Lease, Liability, to be Paid, Total		14,236,000				14,236,000			14,236,000
Lease Commitments [Member]
Finance Lease, Liability, to be Paid, Total		15,900,000				15,900,000			15,900,000
Lessee, Operating Lease, Liability, to be Paid, Total		14,200,000				14,200,000			14,200,000
Performance Obligation Commitments [Member]
Surety Bonds		181,800,000				181,800,000			181,800,000
Letters of Credit Outstanding, Amount		14,900,000				14,900,000			14,900,000
Greens Creek [Member]
EPA Maximum for Statutory Penalties, Per Day/Violation		81,540
EPA Maximum for Administrative Penalties, Per Day/Violation		47,423
Greens Creek [Member] | Purchase Orders and Commitment [Member]
Contractual Obligation, Total		8,100,000				8,100,000			8,100,000
Lucky Friday [Member] | Purchase Orders and Commitment [Member]
Contractual Obligation, Total		19,100,000				19,100,000			19,100,000
Lucky Friday [Member] | Subsequent Event [Member]
EPA Maximum for Statutory Penalties, Per Day/Violation	$ 59,973
EPA Maximum for Administrative Penalties, Per Day/Violation	23,989
EPA Maximum for Administrative Penalties, Total	$ 299,989
Casa Berardi [Member] | Purchase Orders and Commitment [Member]
Contractual Obligation, Total		1,300,000				1,300,000			1,300,000
Nevada Operations [Member] | Purchase Orders and Commitment [Member]
Contractual Obligation, Total		$ 3,400,000				$ 3,400,000			$ 3,400,000
Johnny M Mine Area near San Mateo, New Mexico [Member]
Payment Of Response Costs				$ 1,100,000
Estimated Response Costs			$ 9,600,000					$ 9,000,000.0
Environmental Remediation Expense								9,000,000.0
Johnny M Mine Area near San Mateo, New Mexico [Member] | Environmental Remediation, Past Response Costs [Member]
Accrual for Environmental Loss Contingencies, Period Increase (Decrease), Total								$ 2,900,000
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member]
Estimated Response Costs					$ 4,500,000
Estimated Future Response Cost					$ 100,000,000