XML 64 R31.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Note 10 - Derivative Instruments (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract] |
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] |
December 31, 2015 |  | Ounces/pounds under contract (in 000's) |  |  | Average price per ounce/pound |
|  | Silver (ounces) |  |  | Gold (ounces) |  |  | Zinc (pounds) |  |  | Lead (pounds) |  |  | Silver (ounces) |  |  | Gold (ounces) |  |  | Zinc (pounds) |  |  | Lead (pounds) |
Contracts on provisional sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2016 settlements |  |  | 1,368 |  |  |  | 5 |  |  |  | 23,755 |  |  |  | 8,433 |  |  | $ | 14.12 |  |  | $ | 1,076 |  |  | $ | 0.71 |  |  | $ | 0.77 |
December 31, 2014 |  | Ounces/pounds under contract (in 000's) |  |  | Average price per ounce/pound |
|  | Silver (ounces) |  |  | Gold (ounces) |  |  | Zinc (pounds) |  |  | Lead (pounds) |  |  | Silver (ounces) |  |  | Gold (ounces) |  |  | Zinc (pounds) |  |  | Lead (pounds) |
Contracts on provisional sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2015 settlements |  |  | 1,607 |  |  |  | 6 |  |  |  | 19,456 |  |  |  | 8,378 |  |  |  | 16.06 |  |  |  | 1,195 |  |  | $ | 1.01 |  |  | $ | 0.87 |
Contracts on forecasted sales |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2015 settlements |  |  | N/A |  |  |  | N/A |  |  |  | 46,738 |  |  |  | 29,652 |  |  |  | N/A |  |  |  | N/A |  |  | $ | 0.96 |  |  | $ | 1.07 |
2016 settlements |  |  | N/A |  |  |  | N/A |  |  |  | 44,699 |  |  |  | 34,337 |  |  |  | N/A |  |  |  | N/A |  |  | $ | 0.99 |  |  | $ | 1.03 |
2017 settlements |  |  | N/A |  |  |  | N/A |  |  |  | 1,984 |  |  |  | — |  |  |  | N/A |  |  |  | N/A |  |  | $ | 1.04 |  |  |  | N/A |

X
- References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the notional amounts of outstanding derivative positions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579245-113959 + Details
Name: | us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration