BUSINESS ACQUISITION (Details) (Minera Andes)	0 Months Ended	9 Months Ended
Jan. 24, 2012	Sep. 30, 2013
Minera Andes
BUSINESS ACQUISITION
Exchange ratio	0.45
Exchangeable shares issued	127,331,498
Ratio for exchange of exchangeable shares		1

Represents the exchange ratio to determine the number of shares of the acquirer that shareholders of acquiree entity will receive for each share held.

No definition available.

Name:	mux_BusinessAcquisitionShareExchangeRatio
Namespace Prefix:	mux_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration