Acquisition - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
	May 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Mar. 31, 2024
Business Acquisition [Line Items]
Preliminary estimated goodwill		$ 1,623,760		$ 1,623,760		$ 1,621,763
Issuance of common stock in connection with acquisition					$ 2,123,455
Total revenues		1,122,262	$ 1,225,415	2,248,722	2,005,206
Net losses		137,584	767,238	170,496	844,242
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			426,600		560,800
Net losses			(135,200)		(135,100)
Inmarsat Holdings [Member] | Selling General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition-related transaction costs		$ 0	$ 2,500	$ 0	$ 29,900
Communication Services [Member] | Inmarsat Holdings [Member]
Business Acquisition [Line Items]
Preliminary estimated goodwill	$ 1,500,000