Senior Notes and Other Long-Term Debt - Inmarsat Secured Credit Facilities (Detail) - USD ($)			3 Months Ended		9 Months Ended
	Nov. 21, 2025	Mar. 28, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Mar. 27, 2024
Debt Instrument [Line Items]
Repayments on debt borrowings					$ 798,443,000	$ 2,376,734,000
(Loss) gain on extinguishment of debt, net			$ (11,647,000)	$ (96,614,000)	$ (11,935,000)	$ (99,814,000)
Inmarsat Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility description		In March 2024, Inmarsat amended its then-existing senior secured credit facilities to (among other matters): (1) establish the $1.3 billion Inmarsat Term Loan Facility, the proceeds of which, together with cash on hand, were used to repay approximately $1.38 billion of the outstanding borrowings under the Original Inmarsat Term Loan Facility, resulting in $300.0 million in principal amount of borrowings remaining outstanding under the Original Inmarsat Term Loan Facility at the closing of the amendment, and (2) replace the prior $700.0 million revolving credit facility with a new $550.0 million revolving line of credit (including up to $100.0 million of letters of credit) (the Inmarsat Revolving Credit Facility and, together with the Inmarsat term loan facilities, the Inmarsat Secured Credit Facilities).
Inmarsat Term Loan Facility [Member]
Debt Instrument [Line Items]
Credit facility description					The Inmarsat Secured Credit Facilities contain covenants that restrict, among other things, Inmarsat’s ability to incur additional debt, grant liens, sell assets, make investments and acquisitions, pay dividends and make certain other restricted payments. In addition, covenants regarding Inmarsat’s total net leverage ratio and interest coverage ratio apply to the Inmarsat Revolving Credit Facility. The borrowers under the Inmarsat Secured Credit Facilities were in compliance with the covenants under the Inmarsat Secured Credit Facilities as of December 31, 2025.
Credit Facility maximum borrowing capacity		$ 1,300,000,000	$ 1,300,000,000		$ 1,300,000,000
Outstanding borrowings under the Credit Facility		300,000,000
Repayment of outstanding borrowings under the credit facility		$ 1,380,000,000
Maturity date					Sep. 28, 2029
Line of credit facility, date of first required payment		Jun. 30, 2024
Final installment payment at the maturity date		$ 1,230,000,000
Term loan facility quarterly installments required to be repaid		3,250,000
Credit Facility interest rate description					Borrowings under the Inmarsat Secured Credit Facilities: (1) in the case of borrowings denominated in U.S. Dollars, bear interest, at Inmarsat's option, at either (i) the highest of (x) the federal funds rate plus 0.50%, (y) the forward-looking one-month term SOFR rate plus 1.00% or (z) the administrative agent's prime rate as announced from time to time, or (ii) the forward-looking term SOFR rate for the applicable interest period (subject to, in the case of the Inmarsat Term Loan Facility, a floor of 0.50% per annum and, in the case of the Inmarsat Revolving Credit Facility, a floor of 0.00% per annum), and (2) in the case of borrowings denominated in available currencies other than U.S. Dollars, bear interest based upon the applicable benchmark for such currencies (as described in the Inmarsat Secured Credit Facilities) plus, in all cases, an applicable margin. The applicable margin for the Inmarsat Term Loan Facility is 3.50% per annum for base rate loans and 4.50% per annum for SOFR loans. The applicable margin for borrowings under the Inmarsat Revolving Credit Facility is based on Inmarsat’s total net leverage ratio and ranges between 1.50% and 2.25% per annum for base rate loans and 2.50% and 3.25% per annum for SOFR loans. As of December 31, 2025, the effective interest rate on the Company's outstanding borrowings under the Inmarsat Term Loan Facility was approximately 9.55%. The Inmarsat Secured Credit Facilities are required to be guaranteed by certain material Inmarsat subsidiaries and secured by substantially all of the assets of the Inmarsat borrowers and subsidiary guarantors.
Effective interest rate			9.55%		9.55%
Debt instrument unamortized discount percentage			2.00%		2.00%
Repayments on debt borrowings	$ 300,000,000
(Loss) gain on extinguishment of debt, net			$ (11,600,000)
Inmarsat Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity			550,000,000		$ 550,000,000
Credit Facility maximum borrowing capacity		550,000,000					$ 700,000,000
Maturity date					Mar. 28, 2027
Inmarsat Revolving Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Credit Facility maximum borrowing capacity		$ 100,000,000
Standby letters of credit outstanding amount			$ 0		$ 0