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Stockholders equity note.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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Total change in each class of partners' capital accounts during the year due to redemptions and adjustments to redemption value. All partners include general, limited and preferred partners.

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Number of new stock issued during the period.

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Amount of stock repurchase plan authorized.

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Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands						1 Months Ended			3 Months Ended		6 Months Ended
	Jul. 30, 2020	May 18, 2020	Feb. 14, 2020	Feb. 13, 2020	Mar. 07, 2019	Feb. 29, 2020	Apr. 30, 2019	Jan. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	May 31, 2018
Stockholders Equity Note [Line Items]
Cash proceeds for redemption									$ 3,205,000		$ 3,205,000
Common stock repurchases, value										$ 281,833,000	353,720,000	$ 281,833,000
Common Stock [Member]
Stockholders Equity Note [Line Items]
Cash proceeds for redemption									0		$ 0
Common stock repurchases, Shares										11,005	10,861	11,005
Common stock repurchases, value										$ 110,000	$ 109,000	$ 110,000
Share Repurchase Program [Member] \| Common Stock [Member]
Stockholders Equity Note [Line Items]
Authorized amount of stock repurchase									2,000,000,000.0		2,000,000,000.0		$ 2,000,000,000.0
Repurchase of common stock, remaining amount									4,000,000		4,000,000
Share Repurchase Program Two [Member] \| Common Stock [Member]
Stockholders Equity Note [Line Items]
Authorized amount of stock repurchase						$ 3,000,000,000.0			3,000,000,000.0		3,000,000,000.0
Repurchase of common stock, remaining amount									$ 3,000,000,000.0		$ 3,000,000,000.0
Share Repurchase Program [Member] \| Common Stock [Member]
Stockholders Equity Note [Line Items]
Common stock repurchases, Shares									0	11,000	11,000	11,000
Stock repurchased, average price per share										$ 25.61	$ 32.57	$ 25.61
Common stock repurchases, value										$ 282,000,000	$ 354,000,000	$ 282,000,000
Subsequent Event [Member]
Stockholders Equity Note [Line Items]
Dividends declared per share	$ 0.0025
Dividend paid date	Sep. 15, 2020
Dividend record date	Sep. 10, 2020
MGP BREIT Venture [Member]
Stockholders Equity Note [Line Items]
Issuance of operating partnership units			3,000			3,000
Northfield Operating Company
Stockholders Equity Note [Line Items]
Issuance of operating partnership units							9,000
MGM Growth Properties LLC [Member]
Stockholders Equity Note [Line Items]
Operating partnership units, redeemed		30,000
Cash proceeds for redemption		$ 700,000,000
MGM Growth Properties LLC [Member] \| Class A shares [Member]
Stockholders Equity Note [Line Items]
Issuance of operating partnership units			5,000	13,000				20,000		2,000
New issuance of shares			5,000					20,000		2,000
Number of forward shares settled				13,000
MGM Growth Properties LLC [Member] \| Operating Partnership
Stockholders Equity Note [Line Items]
Partnership interest			60.30%	61.20%	69.80%	60.60%	68.80%	74.60%	56.70%		56.70%
Operating partnership units, redeemed		30,000
Cash proceeds for redemption		$ 700,000,000
MGM Growth Properties LLC [Member] \| MGP [Member] \| Class A shares [Member]
Stockholders Equity Note [Line Items]
Partnership interest								69.70%		68.30%		68.30%
MGM Growth Properties LLC [Member] \| Empire City [Member]
Stockholders Equity Note [Line Items]
Issuance of operating partnership units								13,000
MGM Growth Properties LLC [Member] \| Park MGM [Member]
Stockholders Equity Note [Line Items]
Issuance of operating partnership units					1,000