Note 6 - Business Segments and Sales of Products - Percentage of Sales by Segments (Details) - Revenue Benchmark [Member]	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Percentage of sales	100.00%	100.00%
Greens Creek [Member]
Percentage of sales	53.00%	46.00%
Lucky Friday [Member]
Percentage of sales	1.00%	4.00%
Casa Berardi [Member]
Percentage of sales	26.00%	40.00%
San Sebastian [Member]
Percentage of sales	8.00%	10.00%
Nevada Operations [Member]
Percentage of sales	12.00%

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
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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