LONG-TERM DEBT - Senior Secured Junior Lien Notes (Details) - 6.875% senior secured junior lien notes due in 2031 - USD ($) $ in Millions	12 Months Ended
Dec. 29, 2019	Dec. 30, 2018	Jul. 16, 2018
Debt Instrument [Line Items]
Interest rate (as a percent)	6.875%	6.875%	6.875%
Percentage of premium and accrued and unpaid interest	100.00%
Tranche B
Debt Instrument [Line Items]
Debt conversion amount	$ 75.0

Percentage of principal amount thereof, plus a ?make-whole? premium and accrued and unpaid interest repaid.

No definition available.

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

- Definition

The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=mni_TrancheBTermLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: