Fair Value Measurements - Significant Unobservable Inputs for Fair Value Measurements (Details) $ in Millions	Dec. 31, 2021	Mar. 31, 2020 USD ($)
Gaming licenses
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, fair value		$ 568.0
Trademarks
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, fair value		216.5
Level 3 | Gaming licenses
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, fair value		568.0
Level 3 | Trademarks
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, fair value		$ 216.5
Level 3 | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term Debt, Measurement Input	0.270
Level 3 | Discounted cash flow | Discount rate | Plainridge Park Casino
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent purchase price, measurement input	0.045
Level 3 | Discounted cash flow | Discount rate | Gaming licenses | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.1325
Level 3 | Discounted cash flow | Discount rate | Gaming licenses | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.140
Level 3 | Discounted cash flow | Discount rate | Trademarks | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.1325
Level 3 | Discounted cash flow | Discount rate | Trademarks | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.140
Level 3 | Discounted cash flow | Long-term revenue growth rate | Gaming licenses
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.020
Level 3 | Discounted cash flow | Long-term revenue growth rate | Trademarks
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.020
Level 3 | Discounted cash flow | Pretax royalty rate | Trademarks | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.010
Level 3 | Discounted cash flow | Pretax royalty rate | Trademarks | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Indefinite-lived intangible assets, measurement input		0.020