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Note 8 - Employee Benefit Plans - Employee Allocations of Investments and Measurement Dates by Asset Category (Details) | Dec. 31, 2017 | Dec. 31, 2016
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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 |  | 3.00%
Cash [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments |  | 3.00%
Large Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 19.00% | 18.00%
Large Cap US Equity [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 18.00% | 17.00%
Small Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 9.00% | 9.00%
Small Cap US Equity [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 10.00% | 9.00%
Foreign Government Debt Securities [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 27.00% | 24.00%
Foreign Government Debt Securities [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 26.00% | 25.00%
Fixed Income Funds [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 21.00% | 20.00%
Fixed Income Funds [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 20.00% | 20.00%
Real Estate [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 14.00% | 13.00%
Real Estate [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 15.00% | 13.00%
Hedge Funds [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 5.00% | 6.00%
Hedge Funds [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 6.00% | 6.00%
Common Stock [Member] | Hecla Mining Company Retirement Plan [Member] |  |
Allocation of investments | 5.00% | 7.00%
Common Stock [Member] | Lucky Friday Pension Plan [Member] |  |
Allocation of investments | 5.00% | 7.00%

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- Definition Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2446-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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