XML 53 R31.htm IDEA: XBRL DOCUMENT
v3.8.0.1

INVESTMENTS (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2017
INVESTMENTS |
Summary of investment portfolio |
|  |  |  |  |  |  |  |  |  |  | Other |  | Statement of |  |  |
|  | Opening |  | Additions |  | Disposals |  | Comprehensive |  | Operations |  | Fair Value
|  | balance |  | during |  | during |  | Income (Loss) |  | (Loss) |  | end of the
As of December 31, 2017 |  | (January 1) |  | year |  | year |  | (pre-tax) |  | Income |  | year
Marketable equity securities |  | $ | 6,749 |  | $ | — |  | $ | (2,163) |  | $ | 1,334 |  | $ | 484 |  | $ | 6,404
Warrants |  |  | 1,794 |  |  | — |  |  | — |  |  | — |  |  | (227) |  |  | 1,567
Investments |  | $ | 8,543 |  | $ | — |  | $ | (2,163) |  | $ | 1,334 |  | $ | 257 |  | $ | 7,971
|  |  |  |  |  |  |  |  |  |  | Other |  | Statement of |  |  |
|  | Opening |  | Additions |  | Disposals |  | Comprehensive |  | Operations |  | Fair Value
|  | balance |  | during |  | during |  | Income (Loss) |  | (Loss) |  | end of the
As of December 31, 2016 |  | (January 1) |  | year |  | year |  | (pre-tax) |  | Income |  | year
Marketable equity securities |  | $ | 1,032 |  | $ | 4,004 |  | $ | (470) |  | $ | 3,043 |  | $ | (860) |  | $ | 6,749
Warrants |  |  | — |  |  | 415 |  |  | — |  |  | — |  |  | 1,379 |  |  | 1,794
Investments |  | $ | 1,032 |  | $ | 4,419 |  | $ | (470) |  | $ | 3,043 |  | $ | 519 |  | $ | 8,543

X
- Definition A tabular disclosure of the investment portfolio, which consists of the marketable securities and warrants. + References No definition available. + Details
Name: | mux_ScheduleOfMarketableEquitySecuritiesAndWarrantsTableTextBlock
Namespace Prefix: | mux_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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