Note 4 - Commitments, Contingencies and Obligations (Details) (USD $)	1 Months Ended					3 Months Ended	9 Months Ended
	Aug. 30, 2014	Sep. 30, 2013	Apr. 30, 2013	Aug. 31, 2012	Jun. 30, 2011	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Apr. 30, 2009
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Maximum Environmental Remediation Obligation							$ 2,500,000
Loss Contingency, Estimate of Possible Loss									177,500
Payment Of Response Costs				1,100,000		1,100,000
Other Accrued Liabilities, Noncurrent						300,000
Estimated Response Costs					4,500,000
Estimated Future Response Cost					100,000,000
Loss Contingency, Damages Sought, Value		5,000,000
Proceeds from Issuance of Debt			500,000,000
Debt Instrument, Interest Rate, Stated Percentage		6.875%	6.875%				6.875%
Contractual Obligations		11,500,000					11,500,000
Commitments For Capital Lease Payments		20,800,000					20,800,000
Environmental Expense and Liabilities	55,400,000						1,701,000	3,937,000
Letters of Credit Outstanding, Amount		1,300,000					1,300,000
Casa Berardi [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Open Purchase Orders		13,600,000					13,600,000
Noncapital Costs							3,800,000
Greens Creek [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Open Purchase Orders		5,400,000					5,400,000
Noncapital Costs							200,000
Lucky Friday [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Open Purchase Orders		1,200,000					1,200,000
Noncapital Costs							700,000
Non-Capital Costs [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Contractual Obligations		5,600,000					5,600,000
Costs Incurred By The EPA [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Incurred Response Costs			200,000,000
Minimum [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Loss Contingency, Estimate of Possible Loss						0
Maximum [Member]
Note 4 - Commitments, Contingencies and Obligations (Details) [Line Items]
Loss Contingency, Estimate of Possible Loss						$ 10,000,000