v3.25.4

Income Taxes - Additional Information (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2021
Income Taxes Disclosures [Line Items] |  |  |  |
Income tax examination, description | The German tax authorities have completed examinations up to and including the 2021 tax year for all but one German entity which had its examination completed up to and including the 2019 tax year. The Company is generally not subject to U.S. or Canadian income tax examinations for tax years before 2022 and 2021, respectively. |  |  |
Recognized interest and penalties related to unrecognized tax benefit | $ 0 | $ 0 | $ 0 |
Unrecognized tax benefits | $ 0 | $ 0 |  |
Economic Co-operation and Development |  |  |  |
Income Taxes Disclosures [Line Items] |  |  |  |
Global corporate minimum tax rate of percentage |  |  |  | 15.00%

X
- Definition Global corporate minimum tax rate percentage. + References No definition available. + Details
Name: | merc_GlobalCorporateMinimumTaxRatePercentage
Namespace Prefix: | merc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Income Taxes Disclosures [Line Items] + References No definition available. + Details
Name: | merc_IncomeTaxesDisclosuresLineItems
Namespace Prefix: | merc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition A brief description of status of the tax examination, significant findings to date, and the entity's position with respect to the findings. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_IncomeTaxExaminationDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 217 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-217 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-15A Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 10B -Publisher FASB -URI https://asc.fasb.org/1943274/2147482525/740-10-45-10B + Details
Name: | us-gaap_UnrecognizedTaxBenefits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 217 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-217 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=merc_EconomicCoOperationAndDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |