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Note 10. Derivative Instruments (Detail) - Summary Of Forward Sales Contracts (USD $) | 12 Months Ended
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Dec. 31, 2011 MT | Dec. 31, 2010 MT
2012 Settlements [Member] | Zinc [Member] |  |
Contracts on provisional sales |  |
Metric Tonnes Under Contract | 9,600 |
Average Price Per Pound | $ 0.86 |
Contracts on forecasted sales |  |
Metric Tonnes Under Contract | 20,500 | 21,475
Average Price Per Pound | 1.12 | 1.11
2012 Settlements [Member] | Lead [Member] |  |
Contracts on provisional sales |  |
Metric Tonnes Under Contract | 2,600 |
Average Price Per Pound | 0.89 |
Contracts on forecasted sales |  |
Metric Tonnes Under Contract | 15,900 | 15,000
Average Price Per Pound | 1.12 | 1.11
2013 Settlements [Member] | Zinc [Member] |  |
Contracts on forecasted sales |  |
Metric Tonnes Under Contract | 8,275 |
Average Price Per Pound | 1.14 |
2013 Settlements [Member] | Lead [Member] |  |
Contracts on forecasted sales |  |
Metric Tonnes Under Contract | 11,150 |
Average Price Per Pound | 1.17 |
2011 Settlements [Member] | Zinc [Member] |  |
Contracts on provisional sales |  |
Metric Tonnes Under Contract |  | 11,575
Average Price Per Pound |  | 1.05
Contracts on forecasted sales |  |
Metric Tonnes Under Contract |  | 19,475
Average Price Per Pound |  | 0.96
2011 Settlements [Member] | Lead [Member] |  |
Contracts on provisional sales |  |
Metric Tonnes Under Contract |  | 3,925
Average Price Per Pound |  | 1.11
Contracts on forecasted sales |  |
Metric Tonnes Under Contract |  | 15,550
Average Price Per Pound |  | $ 0.96

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