Income Taxes - Schedule of Benefit (Provision) for Income Taxes Attributable to Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal:
Current			$ (4,928)	$ 11,991	$ (120,980)
Deferred (excluding separate components)			(537,993)	(143,468)	204,713
Deferred – change in enacted rates			0	0	987,942
Deferred – valuation allowance			(20,175)	(19,753)	101,443
Other noncurrent			(5,745)	576	1,356
Benefit (provision) for federal income taxes			(568,841)	(150,654)	1,174,474
State:
Current			(22,685)	(12,564)	(6,798)
Deferred (excluding separate components)			(32,793)	(12,731)	(25,233)
Deferred – operating loss carryforward			(5,241)	(29,490)	44,242
Deferred – valuation allowance			(191)	41,068	(40,078)
Other noncurrent			(1,401)	(1,334)	(3,876)
Provision for state income taxes			(62,311)	(15,051)	(31,743)
Foreign:
Current			(2,454)	(2,037)	(470)
Deferred (excluding separate components)			44,374	63,827	(40,653)
Deferred – operating loss carryforward			32,915	30,574	4,688
Deferred – valuation allowance			(76,028)	23,229	21,098
Benefit (provision) for foreign income taxes			(1,193)	115,593	(15,337)
Benefit (provision) for income taxes	$ (92,000)	$ 72,000	$ (632,345)	$ (50,112)	$ 1,127,394

Deferred federal income tax expense benefit change in enacted rates.

No definition available.

Name:	mgm_DeferredFederalIncomeTaxExpenseBenefitChangeInEnactedRates
Namespace Prefix:	mgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The component of total income tax expense for the period comprised of increase (decrease) in the entity's federal deferred tax assets and liabilities attributable to continuing operations, excluding operating loss and valuation allowance, as determined by applying the provisions of the applicable enacted tax laws.

+ References

No definition available.