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	Dec. 31, 2024	Mar. 31, 2024
Intercompany Revolver | Carrying Value | Revolving 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]
Line of credit facility, fair value disclosure	$ 134.4	$ 0.0
Intercompany Revolver | Fair Value | Revolving Credit Facility | Level 2
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]
Line of credit facility, fair value disclosure	134.4	0.0
LGTV Revolver | Carrying Value | Revolving 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]
Line of credit facility, fair value disclosure	386.8	569.9
LGTV Revolver | Fair Value | Revolving Credit Facility | Level 2
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]
Line of credit facility, fair value disclosure	390.0	575.0
LGTV Term Loan A | Carrying Value | Term 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	313.1	396.6
LGTV Term Loan A | Fair Value | Term Loans | Level 2
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	313.6	397.3
LGTV Term Loan B | Carrying Value | Term 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	0.0	816.9
LGTV Term Loan B | Fair Value | Term Loans | Level 2
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	0.0	818.1
eOne IP Credit Facility | Carrying Value | Line of Credit
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]
Line of credit facility, fair value disclosure	325.8	0.0
eOne IP Credit Facility | Fair Value | Line of Credit | Level 2
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]
Line of credit facility, fair value disclosure	331.5	0.0
LG IP Credit Facility | Carrying Value | Line of Credit
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]
Line of credit facility, fair value disclosure	836.0	0.0
LG IP Credit Facility | Fair Value | Line of Credit | Level 2
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]
Line of credit facility, fair value disclosure	850.0	0.0
Production Loans | Carrying Value | 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	1,342.3	1,286.2
Production Loans | Fair Value | Production Loans | Level 2
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	1,346.0	1,292.2
Production Tax Credit Facility | Carrying Value | Line of Credit
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]
Line of credit facility, fair value disclosure	257.7	258.7
Production Tax Credit Facility | Fair Value | Line of Credit | Level 2
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]
Line of credit facility, fair value disclosure	257.8	260.0
Backlog Facility and Other | Carrying Value | Secured Debt
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, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	178.6	285.4
Backlog Facility and Other | Fair Value | Secured Debt | Level 2
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, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	179.0	287.3
Film Library Facility | Carrying Value | Secured Debt
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, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	85.7	107.6
Film Library Facility | Fair Value | Secured Debt | Level 2
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, IP Credit Facility and Financing component of interest rate swaps, fair value disclosure	$ 87.5	$ 109.9