Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Total revenues	$ 651,444	$ 625,267	$ 1,890,059	$ 1,810,432
Operating profits (losses):
Income (loss) from operations	(31,311)	(28,731)	(83,264)	(64,501)
Amortization of acquired intangible assets	(7,433)	(7,531)	(22,335)	(20,859)
Product [Member]
Revenues:
Total revenues	249,315	226,708	682,769	658,355
Service [Member]
Revenues:
Total revenues	402,129	398,559	1,207,290	1,152,077
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations	(23,878)	(21,200)	(60,929)	(43,642)
Operating Segments [Member] | Satellite Services [Member]
Revenues:
Total revenues	302,412	309,711	915,059	883,938
Operating profits (losses):
Income (loss) from operations	(8,421)	11,459	(13,142)	35,714
Amortization of acquired intangible assets	(7,142)	(7,231)	(21,458)	(19,650)
Operating Segments [Member] | Satellite Services [Member] | Service [Member]
Revenues:
Total revenues	302,412	309,711	915,059	883,938
Operating Segments [Member] | Commercial Networks [Member]
Revenues:
Total revenues	167,223	139,677	460,034	393,079
Operating profits (losses):
Income (loss) from operations	(40,266)	(51,687)	(90,442)	(147,800)
Operating Segments [Member] | Commercial Networks [Member] | Product [Member]
Revenues:
Total revenues	147,163	123,059	400,569	343,525
Operating Segments [Member] | Commercial Networks [Member] | Service [Member]
Revenues:
Total revenues	20,060	16,618	59,465	49,554
Operating Segments [Member] | Government Systems [Member]
Revenues:
Total revenues	181,809	175,879	514,966	533,415
Operating profits (losses):
Income (loss) from operations	24,809	19,028	42,655	68,444
Amortization of acquired intangible assets	(291)	(300)	(877)	(1,209)
Operating Segments [Member] | Government Systems [Member] | Product [Member]
Revenues:
Total revenues	102,152	103,649	282,200	314,830
Operating Segments [Member] | Government Systems [Member] | Service [Member]
Revenues:
Total revenues	79,657	72,230	232,766	218,585
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (7,433)	$ (7,531)	$ (22,335)	$ (20,859)