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Note 11. Derivative Instruments (Detail) - Summary Of Forward Sales Contracts (USD $) | 9 Months Ended
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Sep. 30, 2011
Settlements 2011 [Member] | Zinc [Member] |
Contracts on provisional sales |
2011 settlements (in Dollars) | $ 1.03
Settlements 2011 [Member] | Lead [Member] |
Contracts on provisional sales |
2011 settlements (in Dollars) | 1.00
Settlements 2011 [Member] | Zinc [Member] |
Contracts on provisional sales |
2011 settlements | 5,125
Settlements 2011 [Member] | Lead [Member] |
Contracts on provisional sales |
2011 settlements | 2,800
Settlements 2011 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | 0.99
Settlements 2011 [Member] | Lead [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | 1.05
Settlements 2011 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 2,300
Settlements 2011 [Member] | Lead [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 2,275
Settlements 2012 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | 1.11
Settlements 2012 [Member] | Lead [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | 1.11
Settlements 2012 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 26,650
Settlements 2012 [Member] | Lead [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 18,000
Settlements 2013 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | 1.14
Settlements 2013 [Member] | Lead [Member] |
Contracts on forecasted sales |
Average price per pound - forecasted sales (in Dollars) | $ 1.17
Settlements 2013 [Member] | Zinc [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 8,275
Settlements 2013 [Member] | Lead [Member] |
Contracts on forecasted sales |
Metric tonnes under contract - forecasted sales | 11,150

X
- Definition Average settlement price in forward contracts on forecasted sales + 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 + 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 + 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 + Details
Name: | hl_MetricTonnesUnderContractProvisionalSales
Namespace Prefix: | hl
Data Type: | num:massItemType
Balance Type: | na
Period Type: | instant