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Note 11. Derivative Instruments (Detail) - Summary of base metals committed under forward sales contracts (USD $) | 3 Months Ended
--- | ---
Mar. 31, 2012 | Dec. 31, 2011
Settlements 2012 [Member] | Zinc [Member] |  |
Contracts on provisional sales |  |
Metric tonnes under contract - provisional sales | 6,250 | 9,600
Settlements 2012 [Member] | Lead [Member] |  |
Contracts on provisional sales |  |
Metric tonnes under contract - provisional sales | 1,300 | 2,600
Settlements 2012 [Member] | Zinc [Member] |  |
Contracts on provisional sales |  |
Average price per pound - provisional sales (in Dollars) | $ 0.94 | $ 0.86
Settlements 2012 [Member] | Lead [Member] |  |
Contracts on provisional sales |  |
Average price per pound - provisional sales (in Dollars) | 0.96 | 0.89
Settlements 2012 [Member] | Zinc [Member] |  |
Contracts on forecasted sales |  |
Metric tonnes under contract - forecasted sales | 11,850 | 20,500
Settlements 2012 [Member] | Lead [Member] |  |
Contracts on forecasted sales |  |
Metric tonnes under contract - forecasted sales | 5,100 | 15,900
Settlements 2012 [Member] | Zinc [Member] |  |
Contracts on forecasted sales |  |
Average price per pound - forecasted sales (in Dollars) | 1.12 | 1.12
Settlements 2012 [Member] | Lead [Member] |  |
Contracts on forecasted sales |  |
Average price per pound - forecasted sales (in Dollars) | 1.13 | 1.12
Settlements 2013 [Member] | Zinc [Member] |  |
Contracts on forecasted sales |  |
Metric tonnes under contract - forecasted sales | 8,675 | 8,275
Settlements 2013 [Member] | Lead [Member] |  |
Contracts on forecasted sales |  |
Metric tonnes under contract - forecasted sales | 13,250 | 11,150
Settlements 2013 [Member] | Zinc [Member] |  |
Contracts on forecasted sales |  |
Average price per pound - forecasted sales (in Dollars) | 1.13 | 1.14
Settlements 2013 [Member] | Lead [Member] |  |
Contracts on forecasted sales |  |
Average price per pound - forecasted sales (in Dollars) | $ 1.15 | $ 1.17

X
- Definition Average settlement price in forward contracts on forecasted sales + References No definition available. + Details
Name: | hl_ContractsOnForcastedSales
Namespace Prefix: | hl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | hl_ContractsOnForecastedSalesAbstract
Namespace Prefix: | hl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average settlement price in forward contracts on provisional sales + References No definition available. + Details
Name: | hl_ContractsOnProvisionalSales
Namespace Prefix: | hl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | hl_ContractsOnProvisionalSalesAbstract
Namespace Prefix: | hl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Metric tonnes included in open forward contracts on forecasted sales + References No definition available. + Details
Name: | hl_MetricTonnesUnderContractForecastedSales
Namespace Prefix: | hl_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | instant

X
- Definition Metric tonnes included in open forward contracts on provisional sales + References No definition available. + Details
Name: | hl_MetricTonnesUnderContractProvisionalSales
Namespace Prefix: | hl_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | instant