Amount of accrued employee benefits.

No definition available.

Name:	mni_AccruedEmployeeBenefits
Namespace Prefix:	mni_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of new participants that may enter in the plan.

+ References

No definition available.

+ Details

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

- Definition

Number of employee offered with voluntary early retirement incentive Program.

+ References

No definition available.

+ Details

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

- Definition

The percentage of employees who opted into the voluntary Early Retirement Incentive Program (ERIP).

+ References

No definition available.

+ Details

Name:	mni_PercentageOfEmployeeOptedForVoluntaryEarlyRetirementIncentiveProgram
Namespace Prefix:	mni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of payment, which decreases benefit obligation of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. Excludes decreases to benefit obligation for remeasurement due to settlement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(10)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 15
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=7577095&loc=d3e8001-114927

+ Details

Name:	us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanNameAxis=mni_EarlyRetirementIncentiveProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

EMPLOYEE BENEFITS (Details)	1 Months Ended	3 Months Ended		6 Months Ended
EMPLOYEE BENEFITS (Details)	Feb. 28, 2019 USD ($) employee	Jun. 28, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 28, 2020 USD ($) item	Jun. 30, 2019 USD ($)
EMPLOYEE BENEFITS
Matching contributions		$ 400,000	$ 500,000	$ 900,000	$ 1,100,000
Pension plan
EMPLOYEE BENEFITS
Number of new participants \| item				0
Further benefits		$ 0		$ 0
ERIP
EMPLOYEE BENEFITS
Number of employee offered with voluntary early retirement incentive Program \| employee	450
Percentage of employees opted for voluntary early retirement incentive Program	50.00%
Lump sum pension and termination payments	$ 35,100,000