Number of media companies operated by the entity.

No definition available.

Name:	mni_NumberOfMediaCompanies
Namespace Prefix:	mni_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of phases in the trial.

+ References

No definition available.

+ Details

Name:	mni_NumberOfPhasesInTrial
Namespace Prefix:	mni_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of wholly owned subsidiaries filed voluntary petitions (?Chapter 11 Cases?) for reorganization under Chapter 11 of the U.S. Bankruptcy Code.

+ References

No definition available.

+ Details

Name:	mni_NumberOfWhollyOwnedSubsidiaries
Namespace Prefix:	mni_
Data Type:	xbrli:integerItemType
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

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

- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyNumberOfPlaintiffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=mni_SacramentoCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=mni_FresnoCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
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

Name:	srt_CounterpartyNameAxis=mni_EncinaBusinessCreditLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=mni_RevolvingLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

COMMITMENTS AND CONTINGENCIES - Legal Proceedings (Details) $ in Millions	1 Months Ended		12 Months Ended
	Feb. 28, 2009 item	Dec. 31, 2008 item	Dec. 29, 2019 USD ($) company item	Feb. 13, 2020 subsidiary
Contingencies
Number of media companies \| company			30
Subsequent event
Contingencies
Number of wholly owned subsidiaries \| subsidiary				53
"Sacramento Case"
Contingencies
Number of carriers \| item	5,000
Number of phases \| item			3
"Fresno Case"
Contingencies
Number of carriers \| item		3,500
Number of phases \| item			2
ABL Credit Agreement
Contingencies
Aggregate principal amount \| $			$ 36.6
ABL Credit Agreement \| Letter of credit
Contingencies
Outstanding letters of credit \| $			26.7
DIP Credit Agreement \| Letter of credit \| Encina Business Credit, LLC
Contingencies
Aggregate principal amount \| $			3.5
DIP Credit Agreement \| Revolving loan facility \| Encina Business Credit, LLC
Contingencies
Aggregate principal amount \| $			$ 50.0