XML 99 R75.htm IDEA: XBRL DOCUMENT
v3.20.4

ASSET RETIREMENT OBLIGATIONS - Reclamation and Accretion (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Reclamation obligations |  |  |
Reclamation adjustment reflecting updated estimates | $ (113) | $ 1,851 | $ 2,259
Reclamation accretion | 1,901 | 1,680 | 1,205
Total | $ 1,788 | $ 3,531 | $ 3,464

X
- Definition Amount of reclamation adjustments during the period. + References No definition available. + Details
Name: | mux_ReclamationAdjustments
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of reclamation and remediation expenses. + References No definition available. + Details
Name: | mux_ReclamationAndRemediationExpense
Namespace Prefix: | mux_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 35 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6394232&loc=d3e17558-110866 + Details
Name: | us-gaap_AccretionExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccretionExpenseIncludingAssetRetirementObligationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration