XML 54 R29.htm IDEA: XBRL DOCUMENT
v3.20.1

Note 1 - Basis of Preparation of Financial Statements (Details Textual) - USD ($) $ in Millions |  | 3 Months Ended
--- | --- | ---
Mar. 31, 2020 | Mar. 31, 2020
Casa Berardi [Member] |  |
Suspension Costs |  | $ 0.9
Greens Creek [Member] |  |
Suspension Costs from Quarantining Employee Per Week | $ 0.2 |

X
- Definition Amount of suspension costs during the period. + References No definition available. + Details
Name: | hl_SuspensionCosts
Namespace Prefix: | hl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of costs incurred per week from the employee quarantine. + References No definition available. + Details
Name: | hl_SuspensionCostsFromQuarantiningEmployeePerWeek
Namespace Prefix: | hl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=hl_CasaBerardiMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=hl_GreensCreekMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |