Acquisition - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
	May 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Mar. 31, 2024
Business Acquisition [Line Items]
Preliminary estimated goodwill		$ 1,620,267		$ 1,620,267		$ 1,621,763
Issuance of common stock in connection with acquisition					$ 2,123,455
Total revenues		1,123,767	$ 1,128,539	3,372,489	3,133,745
Net losses		(158,413)	(124,399)	(328,909)	(968,641)
Operating Expense [Member]
Business Acquisition [Line Items]
Severance costs			45,000		45,000
Inmarsat Holdings [Member]
Business Acquisition [Line Items]
Preliminary estimated goodwill	$ 1,462,881
The consideration transferred	2,700,000
Payments to acquire business	550,700
Issuance of common stock in connection with acquisition	$ 2,100,000
Shares issued in connection with acquisition of business, net of issuance costs, shares	46,360
Unfavorable contract liabilities included in current liabilities	$ 29,600
Unfavorable contract liabilities included in other long term liabilities	$ 248,300
Unfavorable contract liabilities weighted average estimated useful life	9 years
Total revenues			443,100		1,000,000
Net losses			(24,200)		(159,300)
Inmarsat Holdings [Member] | Selling General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition-related transaction costs		$ 0	$ 30,800	$ 0	$ 30,800
Communication Services [Member] | Inmarsat Holdings [Member]
Business Acquisition [Line Items]
Preliminary estimated goodwill	$ 1,500,000