Senior Notes and Other Long-Term Debt - Components of Long-Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Finance lease obligations (see Note 7)	$ 26,771	$ 36,405
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	us-gaap:OtherLongTermDebt	us-gaap:OtherLongTermDebt
Total debt	$ 7,475,842	$ 2,490,112
Unamortized discount, debt issuance costs and fair value adjustments made in purchase accounting	(288,553)	(30,672)
Less: current portion of long-term debt	58,054	37,939
Total long-term debt	7,129,235	2,421,501
2031 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	733,400
2028 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	400,000	400,000
2027 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	600,000	600,000
Inmarsat 2026 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	2,075,000
2025 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	700,000	700,000
2022 Term Loan Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	687,750	694,750
2023 Term Loan Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	613,617
Inmarsat Term Loan Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	1,600,000
Ex-Im Credit Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	$ 39,304	$ 58,957