Percentage of fee for early termination under debtor-in-possession financing arrangement.

No definition available.

Name:	mni_DebtorInPossessionFinancingFeeEarlyTermination
Namespace Prefix:	mni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of aggregate undrawn amount of letter of credit required for cash collateral.

+ References

No definition available.

+ Details

Name:	mni_PercentageOfAggregateUndrawnAmountOfLetterOfCreditRequiredForCashCollateral
Namespace Prefix:	mni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount debtor-in-possession financing arranged (but not necessarily all borrowed).

+ References

No definition available.

+ Details

Name:	us-gaap_DebtorInPossessionFinancingAmountArranged
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of fee on unused borrowings under debtor-in-possession financing arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtorInPossessionFinancingFeeOnUnusedBorrowings
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mni_DipCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mni_EncinaBusinessCreditLlcMember
Namespace Prefix:
Data Type:	na
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LONG-TERM DEBT - Credit Agreement (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 29, 2020	Dec. 29, 2019	Jul. 16, 2018
ABL Credit Agreement \| Letter of credit
LONG-TERM DEBT
Outstanding letters of credit	$ 26.7
Percentage of aggregate undrawn amount of letter of credit required to provide cash collateral	102.00%	100.00%
ABL Credit Agreement \| Wells Fargo \| Revolving credit facility
LONG-TERM DEBT
Aggregate principal amount			$ 65.0
ABL Credit Agreement \| Wells Fargo \| Letter of credit
LONG-TERM DEBT
Aggregate principal amount			$ 35.0
DIP Credit Agreement
LONG-TERM DEBT
Aggregate principal amount	$ 12.5
Debtor-in-Possession Financing, Fee on Unused Borrowings	0.50%
Debtor In Possession Financing Fee Early Termination	1.50%
DIP Credit Agreement \| LIBOR
LONG-TERM DEBT
Basis spread on variable rate (as a percent)	3.50%
DIP Credit Agreement \| Base rate
LONG-TERM DEBT
Basis spread on variable rate (as a percent)	1.50%
DIP Credit Agreement \| Minimum \| Federal funds rate
LONG-TERM DEBT
Basis spread on variable rate (as a percent)	0.50%
DIP Credit Agreement \| Maximum \| Federal funds rate
LONG-TERM DEBT
Basis spread on variable rate (as a percent)	1.50%
DIP Credit Agreement \| Encina Business Credit, LLC
LONG-TERM DEBT
Debtor-in-possession financing under a credit agreement	$ 50.0
DIP Credit Agreement \| Encina Business Credit, LLC \| Revolving credit facility
LONG-TERM DEBT
Aggregate principal amount	50.0
DIP Credit Agreement \| Encina Business Credit, LLC \| Letter of credit
LONG-TERM DEBT
Aggregate principal amount	$ 3.5