| **Segment Information - Schedule of Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions** | 3 Months Ended | 6 Months Ended |
|----------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Segment Reporting Information [Line Items]**                                                     |           |           |   |   |
| Revenues                                                                                           | $ 768.5        | $ 582.5        | $ 1,328.0 | $ 946.6 |
| Adjusted EBITDA                                                                                    | 363.7          | 291.2          | 586.6 | 419.7 |
| Live and Historical                                                                                |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                                     |           |           |   |   |
| Revenues                                                                                           | 408.0          | 275.9          | 623.8 | 363.1 |
| Taxes and purses                                                                                   | (85.4)         | (59.6)         | (141.9) | (86.4) |
| Marketing and advertising                                                                          | (12.1)         | (6.4)          | (20.3) | (9.3) |
| Salaries and benefits                                                                              | (30.3)         | (18.9)         | (52.1) | (29.8) |
| Content expense                                                                                    | (2.0)          | (1.0)          | (3.5) | (1.6) |
| Selling, general and administrative expense                                                        | (7.3)          | (3.0)          | (16.0) | (6.3) |
| Other operating expense                                                                            | (47.6)         | (23.2)         | (84.6) | (38.0) |
| Other income                                                                                       | 0.2            | 0.1            | 0.2 | 0.1 |
| Adjusted EBITDA                                                                                    | 223.5          | 163.9          | 305.6 | 191.8 |
| TwinSpires                                                                                         |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                                     |           |           |   |   |
| Revenues                                                                                           | 139.1          | 138.5          | 235.5 | 239.9 |
| Taxes and purses                                                                                   | (7.0)          | (7.2)          | (12.0) | (14.7) |
| Marketing and advertising                                                                          | (5.3)          | (5.0)          | (6.7) | (10.1) |
| Salaries and benefits                                                                              | (7.5)          | (6.9)          | (13.7) | (13.6) |
| Content expense                                                                                    | (68.7)         | (68.1)         | (111.7) | (111.2) |
| Selling, general and administrative expense                                                        | (2.7)          | (2.6)          | (5.1) | (5.2) |
| Other operating expense                                                                            | (14.0)         | (14.8)         | (24.0) | (27.1) |
| Other income                                                                                       | 0.0            | 0.0            | 1.0 | 0.0 |
| Adjusted EBITDA                                                                                    | 33.9           | 33.9           | 63.3 | 58.0 |
| Gaming                                                                                             |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                                     |           |           |   |   |
| Revenues                                                                                           | 247.9          | 184.5          | 499.5 | 363.7 |
| Taxes and purses                                                                                   | (81.7)         | (68.2)         | (165.3) | (135.5) |
| Marketing and advertising                                                                          | (9.0)          | (3.7)          | (17.6) | (7.2) |
| Salaries and benefits                                                                              | (39.5)         | (23.5)         | (74.0) | (47.4) |
| Content expense                                                                                    | (2.7)          | (2.2)          | (4.5) | (3.7) |
| Selling, general and administrative expense                                                        | (10.3)         | (6.7)          | (22.5) | (13.3) |
| Other operating expense                                                                            | (30.0)         | (22.2)         | (60.0) | (42.2) |
| Other income                                                                                       | 48.7           | 48.8           | 97.3 | 83.5 |
| Adjusted EBITDA                                                                                    | $ 123.4        | $ 106.8        | $ 252.9 | $ 197.9 |

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