Note 7 - Business Segments and Sales of Products - Percentage of Sales by Segments (Details) - Sales Revenue, Net [Member]	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Percentage of sales	100.00%	100.00%	100.00%	100.00%
Greens Creek [Member]
Percentage of sales	45.00%	43.00%	48.00%	46.00%
Lucky Friday [Member]
Percentage of sales			2.00%	5.00%
Casa Berardi [Member]
Percentage of sales	37.00%	38.00%	39.00%	33.00%
San Sebastian [Member]
Percentage of sales	10.00%	19.00%	9.00%	16.00%
Nevada Operations [Member]
Percentage of sales	8.00%		2.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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