Basis of Presentation - Summary of Disaggregation of Revenue by Segment and Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Disaggregation Of Revenue [Line Items]
Total revenues	$ 1,171,054	$ 1,126,460
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	344,684	305,739
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	826,370	820,721
Operating Segments [Member] | Communication Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	827,371	826,787
Operating Segments [Member] | Communication Services [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	50,173	60,176
Operating Segments [Member] | Communication Services [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	777,198	766,611
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	343,683	299,673
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	294,511	245,563
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 49,172	$ 54,110