XML 65 R55.htm IDEA: XBRL DOCUMENT
v3.8.0.1

COMMITMENTS AND CONTINGENCIES - Surety, Reclamation Bonds and Flow-Through Common Shares (Details) $ in Thousands, $ in Millions |  |  |  |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Dec. 19, 2017 USD ($) | Sep. 22, 2017 USD ($) | Aug. 25, 2017 USD ($) | Jul. 01, 2017 USD ($) | Jun. 23, 2017 USD ($) | Mar. 31, 2018 CAD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2017 CAD ($) | Dec. 31, 2017 USD ($)
Reclamation Bonds |  |  |  |  |  |  |  |  |
Other assets |  |  |  |  |  |  | $ 9,659 |  | $ 10,718
Amount raised or spent in connection with the equity issuance |  | $ 43,200 |  |  |  |  | 39,400 |  |
Surety Bonds |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Face amount |  |  |  |  | $ 20,000 |  |  |  |
Percentage of annual fees on surety bonds |  |  |  |  | 2.00% |  |  |  |
Percentage of upfront deposit on surety bonds |  |  |  |  | 0.00% |  |  |  |
Surety bonds upfront deposit amount |  |  | $ 15,000 |  |  |  |  |  |
Surety Bonds | Tonkin Project |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Surety bond draw down |  |  |  | $ 3,600 |  |  |  |  |
Surety Bonds | Nevada Exploration Properties |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Surety bond draw down |  |  |  | $ 1,300 |  |  |  |  |
Surety Bonds | Gold Bar project |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Surety bond draw down |  |  | $ 15,000 |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Reclamation bonding obligation |  |  |  |  |  |  | $ 19,900 |  |
Black Fox |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Percentage of upfront deposit on surety bonds |  |  |  |  |  | 2.00% | 2.00% |  |
Surety bonds upfront deposit amount |  |  |  |  |  |  | $ 0 |  |
Surety bonding obligation |  |  |  |  |  | $ 20.6 | 16,500 |  |
Outstanding surety bonds |  |  |  |  |  |  | 20,000 |  |
Timmins |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Surety bonds upfront deposit amount |  |  |  |  |  |  | 100 |  |
Flow Through Common Shares |  |  |  |  |  |  |  |  |
Reclamation Bonds |  |  |  |  |  |  |  |  |
Amount raised or spent in connection with the equity issuance | $ 10,000 |  |  |  |  |  | 1,200 | $ 12.9 | $ 10,000
Total costs incurred for Canadian Exploration Expenditures |  |  |  |  |  |  | $ 3,800 |  |

X
- Definition The value of the outstanding surety bonds. + References No definition available. + Details
Name: | mux_OutstandingSuretyBonds
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition It is a type of performance surety bond. This type of surety bond is required by the Bureau of Land Management (BLM) and also by some state government agencies that issue permits for mining type operations. Reclamation bond amounts are not standard. + References No definition available. + Details
Name: | mux_ReclamationBondsBondingObligation
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the percentage of annual fees on the value of the surety bonds. + References No definition available. + Details
Name: | mux_SuretyBondsAnnualFeesPercentage
Namespace Prefix: | mux_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents a surety bond obligation. It is a promise by a surety or guarantor to pay one party (the obligee) a certain amount if a second party (the principal) fails to meet some obligation, such as fulfilling the terms of a contract. + References No definition available. + Details
Name: | mux_SuretyBondsBondingObligation
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the amount of draw down of surety bonds. + References No definition available. + Details
Name: | mux_SuretyBondsDrewDownAmount
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the amount of upfront deposit on the value of surety bonds. + References No definition available. + Details
Name: | mux_SuretyBondsUpfrontDepositAmount
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the percentage of upfront deposit on the value of the surety bonds. + References No definition available. + Details
Name: | mux_SuretyBondsUpfrontDepositPercentage
Namespace Prefix: | mux_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The total costs incurred as part of Canadian Exploration Expenditures. + References No definition available. + Details
Name: | mux_TotalStockIssuedDuringPeriodValueNewIssuesCostsIncurred
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of noncurrent assets classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_OtherAssetsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodValueNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_SuretyBondMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mux_MineralPropertyNameAxis=mux_TonkinProjectMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mux_MineralPropertyNameAxis=mux_ExplorationPropertiesLocatedInNevadaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mux_MineralPropertyNameAxis=mux_GoldBarProjectMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=mux_ReclamationBondMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=mux_TimminsReportableSegmentMember
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: |