Basis of Presentation and Significant Accounting Policies -Schedule of Increase / (Decrease) By Adopting Accounting Standards in Income Statement Line items (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended					12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Casino	$ 1,394,316				$ 1,271,474
Rooms	539,480				558,812
Food and beverage	455,411				469,336
Entertainment, retail and other	329,750				317,729
Expenses
Casino	762,649				666,935
Rooms	189,058				188,669
Food and beverage	353,389				353,162
Entertainment, retail and other	226,834				223,389
General and administrative	417,890				388,788
Corporate expense	(99,509)				(73,132)
Total expenses	2,494,246				2,260,821
Income from unconsolidated affiliates	31,766				39,766
Operating income	359,757				496,511
Income (loss) before income taxes	180,922				314,714
Benefit (provision) for income taxes	85,379				(62,140)
Net income	266,301				252,574
Net income (loss) attributable to MGM Resorts International	$ 223,444				$ 206,412
Net income per share of common stock attributable to MGM Resorts International
Basic	$ 0.39				$ 0.36
Diluted	$ 0.38				$ 0.36
Accounting Standards Update 2014-09 | Effect Before and After Topic 606 [Member]
Revenues
Casino		$ (241,045)	$ (260,644)	$ (232,305)	$ (233,915)	$ (967,909)	$ (828,364)	$ (782,222)
Rooms		(2,987)	8,518	(715)	(3,455)	1,361	(20,814)	(42,152)
Food and beverage		16,296	21,967	18,552	24,867	81,682	87,895	72,990
Entertainment, retail and other		(1,204)	(2,867)	(3,328)	(1,169)	(8,568)	(9,142)	(10,867)
Total revenues, gross		(228,940)	(233,026)	(217,796)	(213,672)	(893,434)	(770,425)	(762,251)
Promotional allowances		229,297	236,460	228,193	223,059	917,009	793,571	751,773
Total revenues, net		357	3,434	10,397	9,387	23,575	23,146	(10,478)
Expenses
Casino		(147,081)	(147,144)	(135,898)	(137,660)	(567,783)	(504,561)	(519,569)
Rooms		37,260	35,370	34,381	33,833	140,844	121,551	113,560
Food and beverage		100,043	104,786	101,516	103,317	409,662	367,166	353,364
Entertainment, retail and other		10,220	11,779	11,676	10,718	44,393	41,401	39,306
General and administrative		(68)	(111)	(114)	(47)	(340)	(83)	9
Corporate expense		(2)	0	40	(41)	(3)	(69)	(71)
Total expenses		372	4,680	11,601	10,120	26,773	25,405	(13,401)
Income from unconsolidated affiliates		25	89	56	63	233	671	471
Operating income		10	(1,157)	(1,148)	(670)	(2,965)	(1,588)	3,394
Income (loss) before income taxes		10	(1,157)	(1,148)	(670)	(2,965)	(1,588)	3,394
Benefit (provision) for income taxes		(6,310)	405	401	235	(5,269)	556	(1,189)
Net income		(6,300)	(752)	(747)	(435)	(8,234)	(1,032)	2,205
Net income (loss) attributable to MGM Resorts International		$ (6,300)	$ (752)	$ (747)	$ (435)	$ (8,234)	$ (1,032)	$ 2,205
Net income per share of common stock attributable to MGM Resorts International
Basic		$ (0.03)	$ 0	$ (0.01)	$ 0	$ (0.03)	$ 0	$ 0
Diluted		$ (0.03)	$ 0	$ 0	$ 0	$ (0.03)	$ 0	$ 0