XML 49 R37.htm IDEA: XBRL DOCUMENT
v3.23.3

Financial Instruments - Narrative (Details) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2023 | Dec. 31, 2022
Derivative [Line Items] |  |
Restricted cash in other current assets as collateral related to open derivative contracts | $ 1,300,000 | $ 4,000,000
Commodity contracts |  |
Derivative [Line Items] |  |
Deferred net losses, net of tax, included in AOCI | (80,000) |
Cash Flow Hedging | Commodity contracts | Long |  |
Derivative [Line Items] |  |
Open option contracts written, at fair value | $ 18,200,000 |
Time period for open copper future contract purchases | 10 months |
Fair value of future contracts with net gain (loss) position | $ (37,000) |
Fair Value Hedging | Commodity contracts | Short |  |
Derivative [Line Items] |  |
Fair value of future contracts with net gain (loss) position | 97,000 |
Open future contracts to sell copper | $ 6,800,000 |
Time period for open copper future contract sales | 8 months |

X
- Definition Accumulated change, net of tax, in accumulated gains and losses from derivative instruments. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses. + References No definition available. + Details
Name: | mli_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromDerivativeInstrumentsEffectNetOfTax
Namespace Prefix: | mli_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Refers to gain (loss) position on fair value of future contracts. + References No definition available. + Details
Name: | mli_GainLossOnFairValueOfFutureContracts
Namespace Prefix: | mli_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The fair value of the open option contracts Put for the investment. + References No definition available. + Details
Name: | mli_OpenOptionContractsPutAtFairValue
Namespace Prefix: | mli_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Period related to fixed price sales orders of open future contract. + References No definition available. + Details
Name: | mli_TimePeriodForOpenCopperFutureContract
Namespace Prefix: | mli_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period related to fixed price purchase orders of open future contract. + References No definition available. + Details
Name: | mli_TimePeriodForOpenCopperFutureContractSales
Namespace Prefix: | mli_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 55 -Paragraph 13 -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-13 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-20 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (d)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-8 + Details
Name: | us-gaap_DerivativeCollateralObligationToReturnCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |