Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions		12 Months Ended
Aug. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance, beginning of period		$ 317.6	$ 301.5
Additions		20.4	16.1
Balance, end of period		338.0	317.6
Racing
Goodwill [Roll Forward]
Balance, beginning of period		51.7	51.7
Additions		0.0	0.0
Balance, end of period		51.7	51.7
Online Wagering
Goodwill [Roll Forward]
Balance, beginning of period		148.2	132.1
Additions		0.0	16.1
Balance, end of period		148.2	148.2
Casino
Goodwill [Roll Forward]
Balance, beginning of period		117.7	117.7
Additions	$ 20.4	20.4	0.0
Balance, end of period		$ 138.1	$ 117.7

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

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- Definition

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

+ References

No definition available.

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