Acquisitions - Additional Information (Detail) € in Millions			1 Months Ended	3 Months Ended	12 Months Ended
	May 30, 2023 USD ($) shares	Apr. 30, 2021 USD ($) shares	Mar. 31, 2017 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 USD ($) shares	Mar. 31, 2022 USD ($)	May 29, 2023 shares	Apr. 30, 2021 EUR (€)
Business Acquisition [Line Items]
Common stock, shares authorized | shares	200,000,000				200,000,000	200,000,000		100,000,000
Net cash outlay after acquiree's cash on hand					$ 342,621,000		$ 139,533,000
Shares issued in connection with acquisition of business							207,169,000
Total revenues					4,283,758,000	$ 2,556,158,000	2,417,179,000
Net losses					1,068,904,000	(1,084,806,000)	15,534,000
Operating Expense [Member]
Business Acquisition [Line Items]
Severance costs					48,000,000
EBI [Member]
Business Acquisition [Line Items]
Equity method investment ownership percentage			49.00%
EBI Step Acquisition [Member]
Business Acquisition [Line Items]
Percentage of additional interest in subsidiary acquired		51.00%							51.00%
Ownership percentage after completing the acquisition		100.00%							100.00%
The consideration transferred		$ 327,400,000	$ 160,400,000
Payments to acquire business		167,000,000
Euro Infrastructure Co.'s cash on hand		121,700,000
Additional cash received from Euro Broadband Infrastructure Sarl step acquisition				$ 22,000,000
Net cash outlay after acquiree's cash on hand		$ 29,000,000
Contingent consideration arrangements		the Company received €20.0 million, or approximately $22.0 million, in cash and recorded a gain of approximately $18.1 million in the second quarter of fiscal year 2024 in selling, general and administrative expenses in the consolidated statements of operations and comprehensive income (loss)
EBI Step Acquisition [Member] | Maximum [Member]
Business Acquisition [Line Items]
Amount of estimated purchase price consideration to be settled among the parties over the next 24 months from the closing date		$ 22,000,000							€ 20.0
RigNet, Inc [Member]
Business Acquisition [Line Items]
The consideration transferred		317,900,000
Shares issued in connection with acquisition of business		$ 207,200,000
Shares issued in connection with acquisition of business, net of issuance costs, shares | shares		4,000,000
Pay down of outstanding borrowings of acquiree		$ 107,300,000
Remaining amount payable					0
Total revenues							180,200,000
Net losses							31,200,000
RigNet, Inc [Member] | Selling General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Merger-related transaction costs							7,200,000
RigNet, Inc [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration liability		$ 13,800,000
Inmarsat Holdings [Member]
Business Acquisition [Line Items]
The consideration transferred	$ 2,700,000,000
Payments to acquire business	550,700,000
Unfavorable contract liabilities included in current liabilities					29,600,000
Unfavorable contract liabilities included in other long term liabilities					$ 248,300,000
Unfavorable contract liabilities weighted average estimated useful life					9 years
Shares issued in connection with acquisition of business	$ 2,100,000,000
Shares issued in connection with acquisition of business, net of issuance costs, shares | shares	46,360,000
Total revenues					$ 1,400,000,000
Net losses					(214,600,000)
Inmarsat Holdings [Member] | Selling General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition-related transaction costs					$ 31,300,000	$ 40,400,000	$ 26,300,000
Satellite Services [Member] | Inmarsat Holdings [Member]
Business Acquisition [Line Items]
Preliminary estimated goodwill	$ 975,300,000
Government Systems [Member] | Inmarsat Holdings [Member]
Business Acquisition [Line Items]
Preliminary estimated goodwill	$ 487,600,000