Basis of Presentation - Additional Information (Detail 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 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 the Inmarsat Term Loan Facilities of $1.6 billion and mature 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 the Inmarsat 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 new $1.3 billion term loan facility (the New 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)	$ (3,100)	$ 7,900		$ 20,600
Tax on gain (loss) arising from changes in the fair value of the interest rate cap contracts (designated as cash-flow hedging instruments)		2,000		5,200
Derivative contracts gain (loss) reclassified to other comprehensive income and interest expense, net (based on the nature of the underlying transaction)	3,400	(14,300)	$ 8,100	(18,700)
Interest rate cash flow hedge gain loss reclassified to earnings tax expense (benefit)		(3,600)	(2,000)	(4,700)
Cash received	14,400	$ 13,600	28,500	$ 17,800
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	7,500		7,500
Interest Rate Cap [Member] | Other Current Assets [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Interest rate cap contracts	16,600		16,600		$ 44,500
Inmarsat Term Loan Facility [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Principal amount of debt	$ 1,593,500		$ 1,593,500		$ 1,600,000
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						$ 1,600,000
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	2 years		2 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