XML 77 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

INVESTMENTS (Details) $ / shares in Units, $ / shares in Units, $ in Millions | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Dec. 31, 2018 CAD ($) item $ / shares | Dec. 31, 2018 USD ($) item | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 20, 2018 $ / shares | Jan. 01, 2018 USD ($) | Dec. 19, 2017 $ / shares | Apr. 26, 2017 $ / shares
Investments rollforward |  |  |  |  |  |  |  |
Opening balance |  | $ 7,971,000 | $ 8,543,000 |  |  |  |  |
Additions during the year |  | 2,083,000 |  |  |  |  |  |
Net gains (loss) on securities sold |  | (767,000) | 840,000 |  |  |  |  |
Disposals during the year |  | (3,599,000) | (2,163,000) |  |  |  |  |
Other comprehensive (loss) income (pre -tax) |  |  | 1,334,000 |  |  |  |  |
Unrealized gains (loss) on securities held |  | (2,557,000) | (583,000) |  |  |  |  |
Fair Value end of the year |  | 3,131,000 | 7,971,000 | $ 8,543,000 |  |  |  |
Unrealized (loss) gain on derivative instrument |  | (700,000) | (200,000) | 1,400,000 |  |  |  |
Impairment on marketable securities |  | 0 | (400,000) | (900,000) |  |  |  |
Unrealized gain on marketable equity securities, net of taxes |  |  | 1,818,000 | 1,609,000 |  |  |  |
Other-than-temporary impairment on marketable equity securities (note 3) |  |  | (356,000) | (882,000) |  |  |  |
Gain on available-for-sale securities |  |  |  | 100,000 |  |  |  |
Proceeds from sale of investments |  | 2,895,000 | 2,155,000 | 470,000 |  |  |  |
Unrealized gain (loss) on available-for-sale securities (note 3) |  |  | 1,818,000 | 1,609,000 |  |  |  |
Other comprehensive income (loss) |  |  | 840,000 |  |  |  |  |
Cost of purchase of marketable equity securities |  | $ 2,900,000 | 3,300,000 |  |  |  |  |
Price per unit | $ / shares |  |  |  |  |  |  | $ 2.50 |
Common shares per unit |  | 1 |  |  |  |  |  |
Warrants per unit |  | 0.5 |  |  |  |  |  |
Great Bear |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Number of units acquired | item | 786,186 | 786,186 |  |  |  |  |  |
Price per unit | $ / shares | $ 1.45 |  |  |  |  |  |  |
Total cost of private placement transaction | $ 1.1 | $ 900,000 |  |  |  |  |  |
Flow Through Common Shares |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Price per unit | $ / shares |  |  |  |  | $ 2.24 |  |  |
Marketable equity securities |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Opening balance |  | 6,404,000 | 6,749,000 |  |  |  |  |
Additions during the year |  | 1,882,000 |  |  |  |  |  |
Net gains (loss) on securities sold |  | (767,000) | 840,000 |  |  |  |  |
Disposals during the year |  | (2,895,000) | (2,163,000) |  |  |  |  |
Other comprehensive (loss) income (pre -tax) |  |  | 1,334,000 |  |  |  |  |
Unrealized gains (loss) on securities held |  | (1,906,000) | (356,000) |  |  |  |  |
Fair Value end of the year |  | 2,718,000 | 6,404,000 | 6,749,000 |  |  |  |
Warrants |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Opening balance |  | 1,567,000 | 1,794,000 |  |  |  |  |
Additions during the year |  | 201,000 |  |  |  |  |  |
Disposals during the year |  | (704,000) |  |  |  |  |  |
Unrealized gains (loss) on securities held |  | (651,000) | (227,000) |  |  |  |  |
Fair Value end of the year |  | $ 413,000 | $ 1,567,000 | $ 1,794,000 |  |  |  |
Lexam VG Gold |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Price per unit | $ / shares |  |  |  |  |  |  |  | $ 3.00
Accounting Standards Update 2016-01 | Marketable equity securities |  |  |  |  |  |  |  |
Investments rollforward |  |  |  |  |  |  |  |
Cumulative effect of new accounting principle |  |  |  |  |  | $ 3,000,000 |  |

X
- Definition Gross realized gains (losses) on equity securities and warrants. + 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 he number of units acquired by the company in a private placement. Each unit consisting of one common share and one-half common share purchase. + References No definition available. + Details
Name: | mux_NumberOfCommonShareWarrantsPerUnit
Namespace Prefix: | mux_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of common shares per unit, issued under private placement. + References No definition available. + Details
Name: | mux_NumberOfCommonSharesPerUnit
Namespace Prefix: | mux_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of units acquired by the company in a private placement. Each unit consisting of one common share and one-half common share purchase. + References No definition available. + Details
Name: | mux_NumberOfUnitsAcquiredInPrivatePlacement
Namespace Prefix: | mux_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before tax, after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale or trading securities. Excludes amounts related to other than temporary impairment (OTTI) loss. + References No definition available. + Details
Name: | mux_OtherComprehensiveIncomeLossAvailableForSaleAndTradingSecuritiesAdjustmentBeforeTax
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after tax of other than temporary impairment (OTTI) on investments in available-for-sale debt security, recognized in other comprehensive loss, attributable to parent entity. + References No definition available. + Details
Name: | mux_OtherThanTemporaryImpairmentLossesInvestmentsPortionsInOtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAvailableforsaleSecurities
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash outflow for purchase of available for sale and trading securities. + References No definition available. + Details
Name: | mux_PaymentsToAcquireAvailableForSaleAndTradingSecurities
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption. + References No definition available. + Details
Name: | us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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=84241550&loc=SL75117546-209714 + Details
Name: | us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) on investment in marketable security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 + Details
Name: | us-gaap_MarketableSecuritiesUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569643-111683 + Details
Name: | us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e689-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 17A -URI http://asc.fasb.org/extlink&oid=114867106&loc=SL34724391-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash paid to purchase debt and equity securities, classified as operating activities, during the period; includes trading securities and any other investments classified as operating. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585 + Details
Name: | us-gaap_PaymentsForPurchaseOfSecuritiesOperatingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the repurchase of amount received from entity's raising of capital via private rather than public placement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsForRepurchaseOfPrivatePlacement
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period. + References No definition available. + Details
Name: | us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
Name: | us-gaap_SharePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | invest_InvestmentIssuerAxis=mux_GreatBearResourcesLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=mux_IssuanceOfFlowThroughCommonSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=mux_LexamVgGoldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201601Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |