XML 55 R42.htm IDEA: XBRL DOCUMENT
v3.21.1

INVESTMENTS - Activity in Investments (Details) - Marketable equity securities $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2020 USD ($)
Investments rollforward |
Opening balance | $ 1,885
Net gain (loss) on securities sold | (16)
Disposals/transfers during period | (112)
Unrealized (loss) on securities held | (882)
Fair Value end of the period | $ 875

X
- Definition Gross realized gains (losses) on equity securities. + References No definition available. + Details
Name: | mux_AvailableForSaleAndTradingSecuritiesGrossUnrealizedGainLoss
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | mux_InvestmentsRollforward
Namespace Prefix: | mux_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow associated with the sale of equity securities classified as available-for-sale or trading securities. This refers to cash disposals and includes conversions and removals. + References No definition available. + Details
Name: | mux_ProceedsFromDisposalOfAvailableForSaleAndTradingSecurities
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
Name: | us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |