Antidumping fees imposed on certain subsidiaries of the entity.

No definition available.

Name:	mli_AssignmentOfAntidumpingDutyRateOnUSImportsByCompanySubsidiaries
Namespace Prefix:	mli_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Refers to import entries made during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	mli_
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Balance Type:	na
Period Type:	duration

- Definition

Refers to requesting payment for interest and duties related to import entries.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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- Definition

Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

No definition available.

+ Details

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- Details

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Commitments and Contingencies - United States Department of Commerce Antidumping Review (Details)	1 Months Ended	12 Months Ended
	Nov. 27, 2015 USD ($)	Dec. 26, 2020 USD ($)	Dec. 28, 2019 USD ($)	Dec. 29, 2018 USD ($)	Oct. 31, 2008 Import_entry	Apr. 19, 2010
Loss Contingencies [Line Items]
Litigation settlement, net		$ (22,053,000)	$ 0	$ 0
United States Department of Commerce Antidumping Review [Member]
Loss Contingencies [Line Items]
Assignment of antidumping duty rate on U.S. imports by Company subsidiaries						48.33%
Payment request for interest and duties	$ 3,000,000.0
Number of import entries \| Import_entry					795
Deepwater Horizon Economic and Property Damage Claim [Member]
Loss Contingencies [Line Items]
Litigation settlement, net		$ (22,100,000)
Letter of Credit
Loss Contingencies [Line Items]
Letters of credit, guarantees, renewal period		1 year
Letter of Credit \| Revolving Credit Facility
Loss Contingencies [Line Items]
Outstanding letters of credit		$ 22,300,000