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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
	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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Goodwill and intangible assets.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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