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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General discussion of the entity's interest rate cash flow hedge activities.

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Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

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Basis of Presentation - Additional Information (Detail 3) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	May 30, 2023
Interest Rate Cap [Member]
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 in March 2024 (see Note 6 — 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)	$ (3.1)
Derivative contracts gain (loss) reclassified to other comprehensive income and interest expense, net (based on the nature of the underlying transaction)	(3.4)		$ (8.1)
Interest rate cash flow hedge gain loss reclassified to earnings tax expense (benefit)			(2.0)
Cash received	$ 14.4		$ 28.5
Inmarsat Term Loan Facility [Member] \| Interest Rate Cap [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Principal amount of debt				$ 1,600.0
Interest rate cap				2.00%
Maximum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)		38 years
Financing lease, remaining lease term		14 years
Operating lease, remaining lease term		16 years
Maximum [Member] \| Software Development [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)		7 years
Minimum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)		2 years
Financing lease, remaining lease term		1 year
Operating lease, remaining lease term		1 year
Minimum [Member] \| Software Development [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)		3 years