No definition available.

Name:	mux_AssetRetirementObligationAssumptionsAbstract
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- Definition

Inflation rate percentage utilized the following assumptions in the calculation of its asset retirement obligations.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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- Definition

Remediation timeline utilized the following assumptions in the calculation of its asset retirement obligations.

+ References

No definition available.

+ Details

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Data Type:	invest:dateStringItemType
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- Definition

Undiscounted cash flows utilized the following assumptions in the calculation of its asset retirement obligations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Mineral Property Interests [Line Items]

+ References

No definition available.

+ Details

Name:	mux_MineralsPropertyInterestsLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Represents the number of properties of the entity which are subject to reclamation obligations.

+ References

No definition available.

+ Details

Name:	mux_NumberOfPropertiesSubjectToReclamationObligations
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Data Type:	xbrli:integerItemType
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Period Type:	instant

- Definition

Amount of reclamation adjustments during the period.

+ References

No definition available.

+ Details

Name:	mux_ReclamationAdjustments
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of reclamation and remediation expenses.

+ References

No definition available.

+ Details

Name:	mux_ReclamationAndRemediationExpense
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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
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- References

No definition available.

+ Details

Name:	us-gaap_AccretionExpenseIncludingAssetRetirementObligationsAbstract
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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Asset Retirement Obligation
-URI http://asc.fasb.org/extlink&oid=6505190

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- 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

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Balance Type:	na
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- Definition

Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

+ Details

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Balance Type:	credit
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- Details

Name:	mux_MineralPropertyNameAxis=mux_TonkinComplexMember
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RECLAMATION OBLIGATIONS (Details) $ in Thousands		12 Months Ended
RECLAMATION OBLIGATIONS (Details) $ in Thousands	Oct. 03, 2015 USD ($)	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Mineral Property Interests
Number of most significant properties subject to reclamation obligations \| property		2
Surety bonds upfront deposit amount		$ 500
Reclamation obligations
Reclamation Adjustment		89
Reclamation Accretion		506	$ 429	$ 407
Reclamation and remediation expense		595	429	407
Changes in the asset retirement obligations
Asset retirement obligation liability, beginning balance		7,784	7,471
Settlements		(66)
Accretion of liability		506	429	407
Adjustment reflecting updated estimates		1,619	(116)
Asset retirement obligation liability, ending balance		9,843	7,784	$ 7,471
Current portion		(537)	(215)
Non-current portion		9,306	7,569
Asset Retirement Obligation Assumptions
Undiscounted Cash Flows		$ 10,700	$ 9,500
Minimum
Asset Retirement Obligation Assumptions
Remediation timeline		2017	2016
Inflation rate (as a percent)		1.60%	1.40%
Tonkin Complex
Mineral Property Interests
Surety bonds upfront deposit amount	$ 3,600