Note 4 - Commitments, Contingencies and Obligations (Details Textual) - USD ($)		1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended	28 Months Ended
	Apr. 12, 2013	Jun. 30, 2011	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2014	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2014	Dec. 31, 2014
Environmental Remediation Expense			$ 2,940,000	$ 2,162,000		$ 5,044,000	$ 4,779,000
Contractual Obligations			500,000			500,000
Capital Leases, Future Minimum Payments Due			14,101,000			14,101,000
Surety Bonds			117,400,000			117,400,000
Greens Creek [Member]
Open Purchase Orders			20,900,000			20,900,000
Lucky Friday [Member]
Open Purchase Orders			300,000			300,000
Casa Berardi [Member]
Open Purchase Orders			$ 1,900,000			1,900,000
Senior Notes [Member]
Proceeds from Issuance of Debt	$ 500,000,000
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Debt Instrument, Increase (Decrease), Net								$ 6,500,000
Johnny M Mine Area near San Mateo, New Mexico [Member]
Payment Of Response Costs									$ 1,100,000
Estimated Response Costs						5,600,000
Environmental Remediation Expense					$ 5,600,000
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						$ 221,000,000
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member]
Estimated Response Costs		$ 4,500,000
Estimated Future Response Cost		$ 100,000,000
Joint Venture [Member] | Rio Grande Silver Inc and Emerald Mining and Leasing LLC [Member]
Equity Method Investment, Ownership Percentage			70.00%			70.00%
Maximum Environmental Remediation Obligation			$ 2,500,000			$ 2,500,000