Adjusted net revenue to rent ratio.

No definition available.

Name:	mgp_AdjustedNetRevenueToRentRatio
Namespace Prefix:	mgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (Decrease) in Rent Payments Due Under Lease

+ References

No definition available.

+ Details

Name:	mgp_IncreaseDecreaseinRentPaymentsDueUnderLease
Namespace Prefix:	mgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of years that the percentage rent is fixed.

+ References

No definition available.

+ Details

Name:	mgp_InitialPeriodOfFixedRentRemainingTerm
Namespace Prefix:	mgp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Leases.

+ References

No definition available.

+ Details

Name:	mgp_LeasesLineItems
Namespace Prefix:	mgp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Leasing number of extensions of master lease.

+ References

No definition available.

+ Details

Name:	mgp_LeasingNumberOfExtensionsOfMasterLease
Namespace Prefix:	mgp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating Lease, Rent Payments, Percentage At Fixed Rate

+ References

No definition available.

+ Details

Name:	mgp_OperatingLeaseLessorRentPaymentsPercentageAtFixedRate
Namespace Prefix:	mgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating leases fixed amount adjustment multiplier.

+ References

No definition available.

+ Details

Name:	mgp_OperatingLeasesFixedAmountAdjustmentMultiplier
Namespace Prefix:	mgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of aggregate initial rent payments due.

+ References

No definition available.

+ Details

Name:	mgp_PercentageOfAggregateInitialRentPaymentsDue
Namespace Prefix:	mgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Periods for Rent Calculation Subsequent to Initial Term

+ References

No definition available.

+ Details

Name:	mgp_PeriodsforRentCalculationSubsequenttoInitialTerm
Namespace Prefix:	mgp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Rental Revenues Under Master Lease

+ References

No definition available.

+ Details

Name:	mgp_RentalRevenuesUnderMasterLease
Namespace Prefix:	mgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Subsequent Period of Variable Rent Amount

+ References

No definition available.

+ Details

Name:	mgp_SubsequentPeriodofVariableRentAmount
Namespace Prefix:	mgp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessor's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919359-209981

+ Details

Name:	us-gaap_LessorOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lessor's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707

+ Details

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

- Definition

The percentage points added to the reference rate to compute the variable rate on the lessee's operating lease.

+ References

No definition available.

+ Details

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

- Definition

The percentage points added to the reference rate to compute the variable rate on the lessor's operating lease.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_MasterLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_MasterLeaseBaseRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_MasterLeasePercentageRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=mgp_TenantReimbursementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=mgp_MGMNationalHarborCasinoResortMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_MasterLeaseIncreaseInRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_IncreaseInBaseRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mgp_IncreaseInPercentageRentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=mgp_BorgataPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Narrative (Detail) $ in Thousands			12 Months Ended
Leases - Narrative (Detail) $ in Thousands	Oct. 05, 2017 USD ($)	Aug. 01, 2016 USD ($)	Dec. 31, 2018 USD ($) period term	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 18, 2018	Apr. 01, 2018 USD ($)
Leases [Line Items]
Number of lease extension options \| term			4
Additional extension period under Master Lease			5 years
Rent payments due under Master Lease	$ 756,700		$ 770,300
Operating Lease Rent Payments percentage			90.00%
Basis spread on variable rate						2.00%
Adjusted net revenue to rent ratio			625.00%
Number of years that the percentage rent is fixed			6 years
Number of years that percentage rent is variable			5 years
Number of periods for calculation of variable rent \| period			5
Rental revenue			$ 746,253	$ 675,089	$ 419,239
Master Lease
Leases [Line Items]
Initial lease term of Master Lease	10 years		10 years
Additional extension period under Master Lease			5 years
Rental revenue			$ 746,300	675,100	419,200
Base Rent
Leases [Line Items]
Rent payments due under Master Lease		$ 585,000					$ 695,800
Annual rent escalator percentage			2.00%
Percentage Rent
Leases [Line Items]
Percentage of initial total rent payments due under the Master Lease			10.00%
Lease fixed amount adjustment multiplier			1.40%
Tenant Reimbursements
Leases [Line Items]
Rental revenue			$ 123,200	$ 90,600	$ 48,300
MGM National Harbor \| Percentage Rent
Leases [Line Items]
Rent payments due under Master Lease	$ 74,500
MGM National Harbor \| Rent Increase
Leases [Line Items]
Rent payments due under Master Lease	682,200
Rental revenues under Master Lease	95,000
MGM National Harbor \| Base Rent Increase
Leases [Line Items]
Rental revenues under Master Lease	85,500
MGM National Harbor \| Percentage Rent Increase
Leases [Line Items]
Rental revenues under Master Lease	$ 9,500
Borgata \| Master Lease
Leases [Line Items]
Rental revenues under Master Lease		550,000
Borgata \| Percentage Rent
Leases [Line Items]
Rent payments due under Master Lease		65,000
Borgata \| Rent Increase
Leases [Line Items]
Rental revenues under Master Lease		100,000
Borgata \| Base Rent Increase
Leases [Line Items]
Rental revenues under Master Lease		90,000
Borgata \| Percentage Rent Increase
Leases [Line Items]
Rental revenues under Master Lease		$ 10,000