Basis of Presentation - Summary of Disaggregation of Revenue by Segment and Product and Services (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenues	$ 664,860	$ 530,488
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	293,264	250,634
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	371,596	279,854
Operating Segments [Member] | Satellite Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	274,117	201,984
Operating Segments [Member] | Satellite Services [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	274,117	201,984
Operating Segments [Member] | Commercial Networks [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	118,596	67,162
Operating Segments [Member] | Commercial Networks [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	101,531	55,119
Operating Segments [Member] | Commercial Networks [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	17,065	12,043
Operating Segments [Member] | Government Systems [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	272,147	261,342
Operating Segments [Member] | Government Systems [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	191,733	195,515
Operating Segments [Member] | Government Systems [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 80,414	$ 65,827