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Basis of Presentation - Additional Information (Detail 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Mar. 31, 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 provide protection from Compound SOFR rates over 2%, cover the total nominal amount of Inmarsat's senior secured term loan facilities of $1.6 billion and mature at the end of 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 7 — 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 remain 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)		$ (10.0)	$ 1.1	$ 10.6
Tax on gain (loss) arising from changes in the fair value of the interest rate cap contracts (designated as cash-flow hedging instruments)		(2.3)		2.9
Derivative contracts gain (loss) reclassified to other comprehensive income and interest expense, net (based on the nature of the underlying transaction)	$ (5.1)	16.9	(13.2)	(1.8)
Interest rate cash flow hedge gain loss reclassified to earnings tax expense (benefit)	(1.3)	4.0	(3.3)
Cash received	11.5	$ 14.0	40.0	$ 31.8
The estimated net amount of unrealized gains or losses related to the interest rate cap contracts that was expected to be reclassified to earnings net of the recognition into income of non-zero hedge inception fair value within the next 12 months	3.0		3.0
Interest Rate Cap [Member] \| Other Current Assets [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Interest rate cap contracts	$ 6.2		$ 6.2		$ 44.5
Inmarsat Term Loan Facility [Member] \| Interest Rate Cap [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Interest rate cap						2.00%
Principal amount of debt						$ 1,600.0
Maximum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)	38 years		38 years
Financing lease, remaining lease term	15 years		15 years
Operating lease, remaining lease term	17 years		17 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		7 years
Minimum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)	2 years		2 years
Financing lease, remaining lease term	1 year		1 year
Operating lease, remaining lease term	1 year		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		3 years