Note 6 - Business Segments and Sales of Products - Percentage of Sales by Segments (Details) - Revenue Benchmark [Member]	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Percentage of sales	100.00%	100.00%
Greens Creek [Member]
Percentage of sales	39.00%	53.00%
Lucky Friday [Member]
Percentage of sales	2.00%	1.00%
Casa Berardi [Member]
Percentage of sales	34.00%	26.00%
San Sebastian [Member]
Percentage of sales	7.00%	8.00%
Nevada Operations [Member]
Percentage of sales	18.00%	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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-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 275
-SubTopic 10
-Section 50
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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=121572278&loc=d3e13531-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 5: 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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