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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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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

Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

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

- Details

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- Details

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Period Type:

- Details

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Data Type:	na
Balance Type:
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- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mux_NoblegenIncMember
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Data Type:	na
Balance Type:
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- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mux_InventusMember
Namespace Prefix:
Data Type:	na
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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
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Apr. 26, 2017
RELATED PARTY TRANSACTIONS
Accounts payable	$ 38,268		$ 34,880
Entity Affiliated With Related Party \| Lexam L.P.
RELATED PARTY TRANSACTIONS
Expense (income)	27	$ 62
Ownership percentage of individual				27.00%
Entity Affiliated With Related Party \| Lexam L.P. \| Accounts payable
RELATED PARTY TRANSACTIONS
Outstanding accounts payable (receivable)	15		152
Entity Affiliated With Related Party \| Lexam VG Gold
RELATED PARTY TRANSACTIONS
Expense (income)		(33)
Entity Affiliated With Related Party \| Lexam VG Gold \| Accounts payable
RELATED PARTY TRANSACTIONS
Outstanding accounts payable (receivable)			(33)
Entity Affiliated With Related Party \| Noblegen Inc.
RELATED PARTY TRANSACTIONS
Expense (income)	20
Entity Affiliated With Related Party \| Noblegen Inc. \| Accounts payable
RELATED PARTY TRANSACTIONS
Outstanding accounts payable (receivable)	22		40
Entity Affiliated With Related Party \| REVlaw
RELATED PARTY TRANSACTIONS
Expense (income)	17	$ 49
Entity Affiliated With Related Party \| REVlaw \| Accounts payable
RELATED PARTY TRANSACTIONS
Outstanding accounts payable (receivable)	34		330
Entity Affiliated With Related Party \| Inventus
RELATED PARTY TRANSACTIONS
Expense (income)	$ 116
Entity Affiliated With Related Party \| Inventus \| Accounts payable
RELATED PARTY TRANSACTIONS
Outstanding accounts payable (receivable)			$ (36)
Lexam
RELATED PARTY TRANSACTIONS
Interest acquired (as a percent)				100.00%