Senior Notes and Other Long-Term Debt - Components of Long-Term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024
Debt Instrument [Line Items]
Finance lease obligations (see Note 1)	$ 23,666	$ 26,771
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other long-term debt	Other long-term debt
Total debt	$ 7,456,369	$ 7,475,842
Unamortized discount, debt issuance costs and fair value adjustments made in purchase accounting	(269,757)	(288,553)
Less: current portion of long-term debt	57,764	58,054
Total long-term debt	7,128,848	7,129,235
2031 Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt	733,400	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	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	686,000	687,750
2023 Term Loan Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	612,075	613,617
Inmarsat Term Loan Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	1,596,750	1,600,000
Ex-Im Credit Facility [Member]
Debt Instrument [Line Items]
Principal amount of debt	$ 29,478	$ 39,304

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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