Segment Information - Other Acquired Intangible Assets, Net and Goodwill Included in Segment Assets and Amortization of Acquired Intangible Assets by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2021
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	$ 237,850		$ 237,850		$ 9,568
Goodwill	190,907		190,907		122,300
Amortization of acquired intangible assets	7,531	$ 1,313	20,859	$ 4,171
Operating Segments [Member] | Satellite Services [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	235,240		235,240		5,738
Goodwill	82,567		82,567		13,814
Amortization of acquired intangible assets	7,231	557	19,650	1,612
Operating Segments [Member] | Commercial Networks [Member]
Segment Reporting Information [Line Items]
Goodwill	44,083		44,083		44,044
Amortization of acquired intangible assets				257
Operating Segments [Member] | Government Systems [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	2,610		2,610		3,830
Goodwill	64,257		64,257		$ 64,442
Amortization of acquired intangible assets	$ 300	$ 756	$ 1,209	$ 2,302