Basis of Presentation - Summary of Disaggregation of Revenue by Segment and Product and Services (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenues	$ 701,354	$ 554,278	$ 1,366,214	$ 1,084,766
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	308,666	255,980	601,930	506,614
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	392,688	298,298	764,284	578,152
Operating Segments [Member] | Satellite Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	300,110	215,887	574,227	417,871
Operating Segments [Member] | Satellite Services [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	300,110	215,887	574,227	417,871
Operating Segments [Member] | Commercial Networks [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	134,806	78,860	253,402	146,022
Operating Segments [Member] | Commercial Networks [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	118,935	66,751	220,466	121,870
Operating Segments [Member] | Commercial Networks [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	15,871	12,109	32,936	24,152
Operating Segments [Member] | Government Systems [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	266,438	259,531	538,585	520,873
Operating Segments [Member] | Government Systems [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	189,731	189,229	381,464	384,744
Operating Segments [Member] | Government Systems [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 76,707	$ 70,302	$ 157,121	$ 136,129