The ownership percentage of one individual in a related party.

No definition available.

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Namespace Prefix:	mux_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Expenses or income recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

No definition available.

+ Details

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

- Definition

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

+ 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 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mux_NoblegenIncMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=mux_EntityAffiliatedWithRelatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mux_LexamLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mux_RevLawMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mux_LexamMember
Namespace Prefix:
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RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Apr. 26, 2017	Dec. 31, 2016
RELATED PARTY TRANSACTIONS
Accounts payable	$ 25,082		$ 25,082			$ 20,044
Noblegen Inc.
RELATED PARTY TRANSACTIONS
Accounts payable	45		45
Entity Affiliated With Related Party \| Lexam L.P.
RELATED PARTY TRANSACTIONS
Expense (income)		$ 82	90	$ 153
Ownership percentage of individual					27.00%
Entity Affiliated With Related Party \| Lexam VG Gold
RELATED PARTY TRANSACTIONS
Expense (income)		17	(33)	57
Accounts payable						27
Entity Affiliated With Related Party \| REVlaw
RELATED PARTY TRANSACTIONS
Expense (income)	86	$ 38	169	$ 92
Accounts payable	35		35			$ 148
Entity Affiliated With Related Party \| Noblegen Inc.
RELATED PARTY TRANSACTIONS
Expense (income)	$ 40		$ 40
Lexam
RELATED PARTY TRANSACTIONS
Accounts payable					$ 288
Interest acquired (as a percent)					100.00%