Intangible Assets (Changes in Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ (35,958)
Amortization	(14,126)	$ (14,680)	$ (16,366)
Balance, end of period	(135,832)	(35,958)
Indefinite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	(806,988)
Balance, end of period	(1,330,838)	(806,988)
Intangible Assets [Roll Forward]
Balance, beginning of period	(842,946)	(881,954)	(890,054)
Additions	637,850	0	32,680
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		(880)
Impairment of Intangible Assets (Excluding Goodwill)	0	0	24,400
Amortization	(14,126)	(14,680)	(16,366)
Balance, end of period	(1,466,670)	(842,946)	(881,954)
Trademarks
Finite-lived Intangible Assets [Roll Forward]
Amortization	0	0
Indefinite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	(147,587)	(149,387)	(126,001)
Additions	55,500	0	24,200
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0	0
Balance, end of period	(203,087)	(147,587)	(149,387)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		(1,800)
Amortization	0	0
Gaming License Rights
Finite-lived Intangible Assets [Roll Forward]
Amortization	0	0	0
Indefinite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	(659,401)	(659,401)	(683,001)
Additions	468,350	0	0
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0	0	23,600
Balance, end of period	(1,127,751)	(659,401)	(659,401)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		0
Amortization	$ 0	$ 0	0
Customer Relationships
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years 3 months 24 days	5 years 2 months 13 days
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ (5,930)	$ (19,462)	(26,306)
Additions	56,000	0	8,480
Impairments	0	0	0
Amortization	(11,643)	(14,452)	(15,324)
Balance, end of period	(50,287)	(5,930)	(19,462)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		920
Amortization	$ (11,643)	$ (14,452)	(15,324)
Favorable Lease Rates
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	37 years	38 years
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ (8,655)	$ (32,331)	(33,373)
Additions	0	0	0
Impairments	0	0	0
Amortization	(227)	(228)	(1,042)
Balance, end of period	(8,428)	(8,655)	(32,331)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		0
Amortization	$ (227)	$ (228)	(1,042)
Development Agreement
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	0 years	0 years
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ (21,373)	$ (21,373)	(21,373)
Additions	0	0	0
Impairments	0	0	0
Amortization	0	0	0
Balance, end of period	(21,373)	(21,373)	(21,373)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		0
Amortization	$ 0	0	0
Host Relationships [Domain]
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	14 years 4 months 24 days
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ 0	0	0
Additions	58,000	0	0
Impairments	0	0	0
Amortization	(2,256)	0	0
Balance, end of period	(55,744)	0	0
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		0
Amortization	(2,256)	0	0
Borgata
Intangible Assets [Roll Forward]
Balance, beginning of period	(23,448)
Finite-Lived Intangible Assets, Period Increase (Decrease)			(14)
Balance, end of period		(23,448)
Borgata \| Gaming License Rights
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			0
Borgata \| Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	0
Balance, end of period		0
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			0
Borgata \| Favorable Lease Rates
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	(23,448)
Balance, end of period		(23,448)
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			0
Borgata \| Development Agreement
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	0
Balance, end of period		0
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			0
Borgata \| Host Relationships [Domain]
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	0
Balance, end of period		0
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			0
Borgata \| Trademarks
Indefinite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	0
Balance, end of period		0
Borgata \| Gaming License Rights
Indefinite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ 0
Balance, end of period		$ 0
Midwest & South \| Trademarks
Indefinite-lived Intangible Assets [Roll Forward]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)			800
Midwest & South \| Gaming License Rights
Indefinite-lived Intangible Assets [Roll Forward]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)			23,600
Peninsula \| Trademarks
Finite-lived Intangible Assets [Roll Forward]
Amortization			0
Indefinite-lived Intangible Assets [Roll Forward]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)			800
Intangible Assets [Roll Forward]
Amortization			0
Peninsula \| Borgata \| Trademarks
Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			$ (14)
Maximum \| Favorable Lease Rates
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	52 years
Maximum \| Host Relationships [Domain]
Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years

Intangible Assets, Acquired During Period (Excluding Goodwill)

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Intangible Assets [Line Items]

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Intangible Assets [Roll Forward]

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No definition available.

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- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase (decrease) in carrying value of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase (decrease) to assets, excluding financial assets and goodwill, lacking physical substance with a finite life for purchase accounting adjustments.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from an acquisition.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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