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Note 7 - Income and Mining Taxes - Changes in the Valuation Allowance (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Balance at beginning of year | $ (77,210) | $ (86,634) | $ (94,981)
Increase Due to Uncertainty of Recovery [Member] |  |  |
Valuation allowance, deferred tax asset, increase (decrease) | (20,304) | 786 | 686
Decrease Related to Utilization and Expiration [Member] |  |  |
Valuation allowance, deferred tax asset, increase (decrease) | 58,362 | 8,638 | 1,756
Decrease Due to Change in Circumstances and Release of Valuation Allowance [Member] |  |  |
Valuation allowance, deferred tax asset, increase (decrease) | (39,152) | (77,210) | (86,634)
Klondex Mines Ltd [Member] | Business Acquisition [Member] |  |  |
Valuation allowance, deferred tax asset, increase (decrease) | $ 0 | $ 0 | $ 5,905

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
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Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
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- Details
Name: | us-gaap_ValuationAllowanceByDeferredTaxAssetAxis=hl_DecreaseDueToChangeInCircumstancesAndReleaseOfValuationAllowanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
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- Details
Name: | us-gaap_BusinessAcquisitionAxis=hl_KlondexMinesLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |