Goodwill and Acquired Intangible Assets - Allocation of Other Acquired Intangible Assets and Related Accumulated Amortization (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	11 years
Other acquired intangible assets, gross	$ 2,917,299	$ 346,525
Other acquired intangible assets, accumulated amortization	(372,832)	(145,320)
Other acquired intangible assets, net	$ 2,544,467	201,205
Contracts and Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	11 years
Other acquired intangible assets, gross	$ 1,437,738	132,563
Other acquired intangible assets, accumulated amortization	(148,271)	(34,202)
Other acquired intangible assets, net	$ 1,289,467	98,361
Orbital Slots And Spectrum Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	12 years
Other acquired intangible assets, gross	$ 1,088,600	8,600
Other acquired intangible assets, accumulated amortization	(83,600)	(8,600)
Other acquired intangible assets, net	$ 1,005,000
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	7 years
Other acquired intangible assets, gross	$ 251,889	151,327
Other acquired intangible assets, accumulated amortization	(108,414)	(83,949)
Other acquired intangible assets, net	$ 143,475	67,378
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	8 years
Other acquired intangible assets, gross	$ 117,280	32,253
Other acquired intangible assets, accumulated amortization	(24,770)	(12,657)
Other acquired intangible assets, net	$ 92,510	19,596
Other [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	11 years
Other acquired intangible assets, gross	$ 21,792	21,782
Other acquired intangible assets, accumulated amortization	(7,777)	(5,912)
Other acquired intangible assets, net	$ 14,015	$ 15,870