Note 10 - Commitments, Contingencies and Obligations (Details Textual) - USD ($) $ in Thousands			1 Months Ended			3 Months Ended
	Jul. 12, 2022	Jun. 30, 2022	Jul. 31, 2018	Aug. 31, 2012	Jun. 30, 2011	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Loss Contingencies [Line Items]
Environmental remediation expense						$ 1,044	$ 901
Finance lease, liability, to be paid						20,656
Lessee, operating lease, liability, to be paid						13,933
Lease Commitments [Member]
Loss Contingencies [Line Items]
Finance lease, liability, to be paid						20,700
Lessee, operating lease, liability, to be paid						13,900
Performance Obligation Commitments [Member]
Loss Contingencies [Line Items]
Surety Bonds						192,800
Letters of credit outstanding, amount						6,700
Greens Creek [Member]
Loss Contingencies [Line Items]
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]
Loss Contingencies [Line Items]
Contractual obligation						15,200
Lucky Friday [Member]
Loss Contingencies [Line Items]
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	$ 299,989
Lucky Friday [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						29,400
Casa Berardi [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						1,300
Nevada Operations [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						1,400
Keno Hill [Member] | Purchase Orders and Commitment [Member]
Loss Contingencies [Line Items]
Contractual obligation						$ 3,700
Johnny M Mine Area near San Mateo, New Mexico [Member]
Loss Contingencies [Line Items]
Payment of response costs				$ 1,100
Estimated response costs			$ 9,600
Environmental remediation expense								$ 9,000
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)								$ 9,000
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member]
Loss Contingencies [Line Items]
Estimated response costs					$ 4,500
Estimated future response cost					$ 100,000