XML 40 R29.htm IDEA: XBRL DOCUMENT
v3.21.2

INVESTMENTS (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2021
INVESTMENTS |
Summary of investment portfolio | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As at | ​ | Additions/ | ​ | ​ | ​ | Disposals/ | ​ | Unrealized | ​ | Fair value
​ | ​ | December 31, | ​ | transfers during | ​ | Net gain (loss) on | ​ | transfers during | ​ | gain on | ​ | September 30,
​ |  | 2020 |  | period |  | securities sold |  | year |  | securities held |  | 2021
Marketable equity securities | ​ | $ | — | ​ | $ | 1,616 | ​ | $ | — | ​ | $ | — | ​ | $ | 20 | ​ | $ | 1,636
Warrants | ​ |  | — | ​ |  | 162 | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 162
Investments | ​ | $ | — | ​ | $ | 1,777 | ​ | $ | — | ​ | $ | — | ​ | $ | 20 | ​ | $ | 1,798
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As at | ​ | Additions/ | ​ | Net | ​ | Disposals/ | ​ | Unrealized | ​ | Fair value
​ | ​ | December 31, | ​ | transfers during | ​ | (loss) on | ​ | transfers during | ​ | (loss) on | ​ | September 30,
​ |  | 2019 |  | period |  | securities sold | ​ | year | ​ | securities held | ​ | 2020
Marketable equity securities | ​ | $ | 1,885 | ​ | $ | — | ​ | $ | (619) | ​ | $ | (1,266) | ​ | $ | — | ​ | $ | —

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: | dtr-types: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