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Goodwill and Other Intangible Assets - Summary of Changes in Company's Goodwill by Reportable Segment (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Goodwill And Intangible Assets [Line Items] |  |
Goodwill, beginning balance | $ 2,084,564 | $ 1,821,392
Acquisitions | 0 | 256,133
Reclassifications | 0 | 0
Currency exchange | 6,714 | 7,039
Goodwill, ending balance | 2,091,278 | 2,084,564
Las Vegas Strip Resorts [Member] |  |
Goodwill And Intangible Assets [Line Items] |  |
Goodwill, beginning balance | 30,452 | 70,975
Acquisitions | 0 | 0
Reclassifications | 0 | (40,523)
Currency exchange | 0 | 0
Goodwill, ending balance | 30,452 | 30,452
Regional Operations [Member] |  |
Goodwill And Intangible Assets [Line Items] |  |
Goodwill, beginning balance | 701,463 | 386,892
Acquisitions | 0 | 256,133
Reclassifications | 0 | 58,438
Currency exchange | 0 | 0
Goodwill, ending balance | 701,463 | 701,463
MGM China [Member] |  |
Goodwill And Intangible Assets [Line Items] |  |
Goodwill, beginning balance | 1,352,649 | 1,345,610
Acquisitions | 0 | 0
Reclassifications | 0 | 0
Currency exchange | 6,714 | 7,039
Goodwill, ending balance | 1,359,363 | 1,352,649
Corporate and Other [Member] |  |
Goodwill And Intangible Assets [Line Items] |  |
Goodwill, beginning balance | $ 0 | 17,915
Acquisitions |  | 0
Reclassifications |  | (17,915)
Currency exchange |  | 0
Goodwill, ending balance |  | $ 0

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