Fair Value Measurements - Schedule of Carrying Values and Fair Values of Company’s Outstanding Debt, Film Related Obligations, and Interest Rate Swaps (Details) - USD ($) $ in Millions	Jun. 30, 2026	Mar. 31, 2026
Carrying Value \| Revolving Credit Facility \| The Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	$ 0.0	$ 0.0
Carrying Value \| Senior Notes \| Senior Notes
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Senior notes fair value disclosure	383.5	383.1
Carrying Value \| Line of Credit \| eOne IP Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	357.8	366.7
Carrying Value \| Line of Credit \| LG IP Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	1,142.3	1,172.5
Carrying Value \| Line of Credit \| 3 Arts Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	30.2	30.1
Carrying Value \| Line of Credit \| Production Tax Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	364.6	364.8
Carrying Value \| Production Loans \| Production Loans
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	1,361.1	1,280.5
Carrying Value \| Secured Debt \| Backlog Facility and Other
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other	310.8	304.6
Fair Value \| Fair Value (Level 2) \| Revolving Credit Facility \| The Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	0.0	0.0
Fair Value \| Fair Value (Level 2) \| Senior Notes \| Senior Notes
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Senior notes fair value disclosure	370.4	359.6
Fair Value \| Fair Value (Level 2) \| Line of Credit \| eOne IP Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	362.0	371.3
Fair Value \| Fair Value (Level 2) \| Line of Credit \| LG IP Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	1,156.3	1,187.5
Fair Value \| Fair Value (Level 2) \| Line of Credit \| 3 Arts Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	30.7	30.7
Fair Value \| Fair Value (Level 2) \| Line of Credit \| Production Tax Credit Facility
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Lines of credit, fair value disclosure	367.4	368.0
Fair Value \| Fair Value (Level 2) \| Production Loans \| Production Loans
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Loans, fair value disclosure	1,364.7	1,283.9
Fair Value \| Fair Value (Level 2) \| Secured Debt \| Backlog Facility and Other
Fair Value, Carrying Values and Fair Values of Assets and Liabilities Not Required to be Carried at Fair Value on a Recurring Basis [Line Items]
Backlog Facility and Other	$ 313.2	$ 307.2