v3.25.4

Accounts Payable and Other - Schedule of Accounts Payable and Other (Parenthetical) (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Payables and Accruals [Abstract] |  |  |
Revenues recognized | $ 4,345,000 | $ 15,262,000 |
Reductions to wastewater fees | $ 0 | $ 2,189,000 | $ 4,348,000

X
- Definition Reductions to wastewater fees. + References No definition available. + Details
Name: | merc_ReductionsToWastewaterFees
Namespace Prefix: | merc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-8 + Details
Name: | us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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