Acquisitions - Narrative (Details) $ in Millions			3 Months Ended		12 Months Ended
	Jun. 05, 2024 USD ($) film	Dec. 27, 2023 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)
Business Acquisition [Line Items]
Number of films acquired | film	46
Variable interest entity, initial consolidation, gain (loss)	$ 0.0
Total assets			$ 5,115.2	$ 5,103.0	$ 5,115.2	$ 5,103.0
Liabilities			6,038.1	6,129.9	6,038.1	6,129.9
Variable Interest Entity, Primary Beneficiary
Business Acquisition [Line Items]
Total assets			63.3		63.3
Liabilities			7.7		7.7
CP LG Library Holdings, LLC
Business Acquisition [Line Items]
Asset acquisition, consideration transferred	68.6
Film and Television Library | CP LG Library Holdings, LLC
Business Acquisition [Line Items]
Asset acquisition, consideration transferred	48.3
CP LG Library Holdings, LLC
Business Acquisition [Line Items]
Consideration transferred	$ 35.0
Percentage of voting interests acquired	51.00%
eOne
Business Acquisition [Line Items]
Consideration transferred		$ 373.1	$ 373.1
Revenue of acquiree since acquisition date, actual				113.8
Earnings or loss of acquiree since acquisition date, actual				$ 4.9
Acquisition related costs					$ 1.0	9.4
Pro forma impairment of goodwill and trade name at eOne						$ 296.2
eOne | Trade Names
Business Acquisition [Line Items]
Weighted average useful life (in years)		5 years
eOne | Minimum | Film and Television Library
Business Acquisition [Line Items]
Weighted average useful life (in years)		5 years
eOne | Maximum | Film and Television Library
Business Acquisition [Line Items]
Weighted average useful life (in years)		10 years
CP LG Library Holdings, LLC
Business Acquisition [Line Items]
Ownership percentage by noncontrolling owners	49.00%