XML 43 R31.htm IDEA: XBRL DOCUMENT
v3.20.2

Investments in and Advances to Unconsolidated Affiliates - Schedule of Investments in and Advances to Unconsolidated Affiliates (Detail) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Schedule Of Equity Method Investments [Line Items] |  |
Investments in and advances to unconsolidated affiliates | $ 1,473,955 | $ 822,366
CityCenter Holdings LLC As Investee [Member] |  |
Schedule Of Equity Method Investments [Line Items] |  |
Investments in and advances to unconsolidated affiliates | 454,767 | 568,879
MGP BREIT Venture [Member] |  |
Schedule Of Equity Method Investments [Line Items] |  |
Investments in and advances to unconsolidated affiliates | 807,936 | 0
Other [Member] |  |
Schedule Of Equity Method Investments [Line Items] |  |
Investments in and advances to unconsolidated affiliates | $ 211,252 | $ 253,487

X
- Definition Amount of investment in equity method investee and investment in and advance to affiliate. + 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 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mgm_CityCenterHoldingsLLCAsInvesteeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mgm_MGPBREITVentureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mgm_OtherUnconsolidatedAffiliatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |