The Company and a Summary of Its Significant Accounting Policies - Additional Information (Detail 4) - Interest Rate Cap [Member] - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2025	Mar. 31, 2024	May 30, 2023
Company And Summary Of Significant Accounting Policies [Line Items]
Interest rate cap contracts, description	The interest rate cap contracts provided protection from Compound SOFR rates over 2%, covered the total nominal amount of Inmarsat's senior secured term loan facilities of $1.6 billion, and matured in February 2025. At the time of the acquisition, the Company continued to account for the interest rate cap contracts as cash-flow hedges. Upon amendment of Inmarsat's senior secured term loan facilities on March 28, 2024 (see Note 8 — Senior Notes and Other Long-Term Debt for more information), the portion of the interest rate cap contracts related to Inmarsat's $1.3 billion senior secured term loan facility (the 2024 Inmarsat Term Loan Facility) continued to be accounted for as cash-flow hedges, as the interest rate cap contracts remained in place with their original maturity date.
Gain (loss) in other comprehensive income arising from changes in the fair value of derivative contracts (designated as cash-flow hedging instruments)	$ 1.2	$ 20.2
Tax on gain (loss) arising from changes in the fair value of the interest rate cap contracts (designated as cash-flow hedging instruments)		5.1
Derivative contracts gain (loss) reclassified to other comprehensive income and interest expense, net (based on the nature of the underlying transaction)	15.9	5.5
Interest rate cash flow hedge gain loss reclassified to earnings tax expense (benefit)	4.0	1.4
Cash received	$ 46.3	45.6
Other Current Assets [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Interest rate cap contracts		$ 44.5
Inmarsat Term Loan Facility [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Principal amount of debt			$ 1,600.0
Interest rate cap			2.00%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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