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Note 9 - Employee Benefit Plans - Employee Allocations of Investments and Measurement Dates by Asset Category (Details) | Dec. 31, 2020 | Dec. 31, 2019
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Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 100.00% | 100.00%
Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 100.00% | 100.00%
Cash [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 0.00% | 6.00%
Cash [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 0.00% | 6.00%
Large Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 17.00% | 14.00%
Large Cap US Equity [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 16.00% | 14.00%
Small Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 8.00% | 7.00%
Small Cap US Equity [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 9.00% | 7.00%
Debt Security, Government, Non-US [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 26.00% | 22.00%
Debt Security, Government, Non-US [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 26.00% | 22.00%
Fixed Income Funds [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 21.00% | 19.00%
Fixed Income Funds [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 21.00% | 19.00%
Real Estate [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 11.00% | 14.00%
Real Estate [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 12.00% | 15.00%
Hedge Funds [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 5.00% | 5.00%
Hedge Funds [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 4.00% | 5.00%
Common Stock [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 12.00% | 13.00%
Common Stock [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 12.00% | 12.00%

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- Definition Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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