XML 14 R33.htm IDEA: XBRL DOCUMENT
v2.4.0.6

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2012 | Jan. 24, 2012 MSC | Jan. 24, 2012 Minera Andes MSC | Jan. 24, 2012 Minera Andes Los Azules Copper Deposit
Nature of Operations and Basis of Presentation |  |  |  |
Period for determining current portion of ore stockpiles | 12 months |  |  |
Period within which ore stockpile inventories are not expected to be processed, classified as long-term | 12 months |  |  |
Interest acquired (as a percent) |  | 49.00% | 49.00% | 100.00%

X
- Definition Represents the period within which ore stockpile inventories are not expected to be processed and classified as long-term. + References No definition available. + Details
Name: | mux_PeriodForClassifyingOreStockpileInventoryAsLongTerm
Namespace Prefix: | mux_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the period for determining the current portion of the ore stockpile inventory. + References No definition available. + Details
Name: | mux_PeriodForDeterminingCurrentPortionOfOreStockpileInventory
Namespace Prefix: | mux_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of voting equity interests acquired in the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7659399&loc=d3e1392-128463 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant