Represents the amount of amortization expense related to the mineral property interests.

No definition available.

Name:	mux_MineralPropertyInterestsAmortization
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of amortization expense related to the mineral property interests and capitalized asset retirement costs.

+ References

No definition available.

+ Details

Name:	mux_MineralPropertyInterestsAndAssetRetirementObligationsAmortization
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Mineral Property Interests [Line Items]

+ References

No definition available.

+ Details

Name:	mux_MineralsPropertyInterestsLineItems
Namespace Prefix:	mux_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Mineral properties, net of adjustments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 360
-Section 25
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64895-109465

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_MineralPropertiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow from the purchase of mining and mining related assets during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireMiningAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	mux_MineralPropertyNameAxis=mux_ElGalloComplexMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

MINERAL PROPERTY INTEREST - Mineral Property Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Apr. 26, 2017	Dec. 31, 2016
Mineral Property Interests
Purchase price				$ 5,950
Mineral property interests	$ 283,170		$ 283,170			$ 242,640
Amortization of mineral property interests and asset retirement obligations			1,065	1,144
El Gallo 1 mine
Mineral Property Interests
Amortization of mineral property interests	$ 600	$ 800	$ 1,100	$ 1,100
Lexam VG Gold
Mineral Property Interests
Mineral property interests					$ 41,600