Name:	mux_ContractualObligationToBePaidAfterYearFour
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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

Amount of lessee's undiscounted obligation for lease payments..

No definition available.

Name:	mux_LeaseLiabilityPaymentsDue
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of lessee's undiscounted obligation for lease payments, due after fifth fiscal year following latest fiscal year.

No definition available.

Name:	mux_LeaseLiabilityPaymentsDueAfterYearFive
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in next fiscal year.

No definition available.

Name:	mux_LeaseLiabilityPaymentsDueNextTwelveMonths
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of lessee's undiscounted obligation for lease payments, due in fourth fiscal year following latest fiscal year.

No definition available.

Name:	mux_LeaseLiabilityPaymentsDueYearFour
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of lessee's undiscounted obligation for lease payments , due in third fiscal year following latest fiscal year.

No definition available.

Name:	mux_LeaseLiabilityPaymentsDueYearThree
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of lessee's undiscounted obligation for lease payments , due in second fiscal year following latest fiscal year.

No definition available.

Name:	mux_LeaseLiabilityPaymentsDueYearTwo
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

n/a

No definition available.

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

Amount of required minimum rental payments for leases for mining and surface rights having an initial or remaining non-cancelable letter-terms in excess of one year.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDue
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for operating leases for mining and surface rights having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDueInFourYears
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for operating leases for mining and surface rights having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDueInNextTwelveMonths
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for operating leases for mining and surface rights having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDueInThreeYears
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for operating leases for mining and surface rights having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDueInTwoYears
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for operating leases for mining and surface rights having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	mux_OperatingLeasesFutureMinimumPaymentsDueMiningAndSurfaceRightsDueThereafter
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Minimum amount of reclamation costs.

No definition available.

Name:	mux_ReclamationCosts
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing in the fourth fiscal year following the latest fiscal year.

No definition available.

Name:	mux_ReclamationCostsDueInFourthYear
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing in the next fiscal year following the latest fiscal year.

No definition available.

Name:	mux_ReclamationCostsDueInNextTwelveMonths
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing in the second fiscal year following the latest fiscal year.

No definition available.

Name:	mux_ReclamationCostsDueInSecondYear
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing in the third fiscal year following the latest fiscal year.

No definition available.

Name:	mux_ReclamationCostsDueInThirdYear
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing after the fifth fiscal year.

No definition available.

Name:	mux_ReclamationCostsDueThereafter
Namespace Prefix:	mux_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Minimum amount of reclamation costs maturing in the next fiscal year following the latest fiscal year.

No definition available.

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

Amount of contractual obligation, including, but not limited to, long-term debt, lease obligation, purchase obligation, and other commitments.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

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

Amount of contractual obligation to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

- References

No definition available.