Basis of Presentation - Summary of Disaggregation of Revenue by Segment and Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation Of Revenue [Line Items]
Total revenues	$ 1,122,262	$ 1,225,415	$ 2,248,722	$ 2,005,206
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	323,948	401,729	629,687	638,101
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	798,314	823,686	1,619,035	1,367,105
Operating Segments [Member] | Communication Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	826,385	846,557	1,653,172	1,406,817
Operating Segments [Member] | Communication Services [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	78,491	75,795	138,667	142,282
Operating Segments [Member] | Communication Services [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	747,894	770,762	1,514,505	1,264,535
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	295,877	378,858	595,550	598,389
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	245,457	325,934	491,020	495,819
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 50,420	$ 52,924	$ 104,530	$ 102,570