Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Total revenues	$ 1,122,262	$ 1,225,415	$ 2,248,722	$ 2,005,206
Operating profits (losses):
Income (loss) from operations	(24,678)	(804,667)	35,057	(846,183)
Amortization of acquired intangible assets	(66,024)	(81,374)	(132,239)	(109,185)
Product [Member]
Revenues:
Total revenues	323,948	401,729	629,687	638,101
Service [Member]
Revenues:
Total revenues	798,314	823,686	1,619,035	1,367,105
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations	41,346	(723,293)	167,296	(736,998)
Operating Segments [Member] | Communication Services [Member]
Revenues:
Total revenues	826,385	846,557	1,653,172	1,406,817
Operating profits (losses):
Income (loss) from operations	(467)	(831,186)	41,472	(841,129)
Operating Segments [Member] | Communication Services [Member] | Government Satcom Services [Member]
Revenues:
Total revenues	179,875	169,843	363,748	252,467
Operating Segments [Member] | Communication Services [Member] | Aviation Services [Member]
Revenues:
Total revenues	261,987	224,049	519,142	375,161
Operating Segments [Member] | Communication Services [Member] | Maritime Services [Member]
Revenues:
Total revenues	121,179	130,428	245,126	175,773
Operating Segments [Member] | Communication Services [Member] | Fixed Services and Other Services [Member]
Revenues:
Total revenues	184,853	246,442	386,489	461,134
Operating Segments [Member] | Communication Services [Member] | Product [Member]
Revenues:
Total revenues	78,491	75,795	138,667	142,282
Operating Segments [Member] | Communication Services [Member] | Service [Member]
Revenues:
Total revenues	747,894	770,762	1,514,505	1,264,535
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Revenues:
Total revenues	295,877	378,858	595,550	598,389
Operating profits (losses):
Income (loss) from operations	41,813	107,893	125,824	104,131
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Information Security and Cyber Defense Products [Member]
Revenues:
Total revenues	83,548	82,378	139,055	139,054
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Space and Mission Systems Products [Member]
Revenues:
Total revenues	78,782	92,306	152,088	164,693
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Tactical Networking Products [Member]
Revenues:
Total revenues	80,034	42,445	151,444	79,829
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Advanced Technologies and Other Products [Member]
Revenues:
Total revenues	3,093	108,805	48,433	112,243
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Product [Member]
Revenues:
Total revenues	245,457	325,934	491,020	495,819
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Service [Member]
Revenues:
Total revenues	50,420	52,924	104,530	102,570
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (66,024)	$ (81,374)	$ (132,239)	$ (109,185)