Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Total revenues	$ 664,860	$ 530,488
Operating profits (losses):
Income (loss) from operations	16,292	(5,314)
Amortization of acquired intangible assets	(5,929)	(1,558)
Product [Member]
Revenues:
Total revenues	293,264	250,634
Service [Member]
Revenues:
Total revenues	371,596	279,854
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations	22,221	(3,756)
Operating Segments [Member] | Satellite Services [Member]
Revenues:
Total revenues	274,117	201,984
Operating profits (losses):
Income (loss) from operations	12,513	(1,857)
Amortization of acquired intangible assets	(5,322)	(509)
Operating Segments [Member] | Satellite Services [Member] | Service [Member]
Revenues:
Total revenues	274,117	201,984
Operating Segments [Member] | Commercial Networks [Member]
Revenues:
Total revenues	118,596	67,162
Operating profits (losses):
Income (loss) from operations	(37,708)	(51,394)
Amortization of acquired intangible assets		(257)
Operating Segments [Member] | Commercial Networks [Member] | Product [Member]
Revenues:
Total revenues	101,531	55,119
Operating Segments [Member] | Commercial Networks [Member] | Service [Member]
Revenues:
Total revenues	17,065	12,043
Operating Segments [Member] | Government Systems [Member]
Revenues:
Total revenues	272,147	261,342
Operating profits (losses):
Income (loss) from operations	47,416	49,495
Amortization of acquired intangible assets	(607)	(792)
Operating Segments [Member] | Government Systems [Member] | Product [Member]
Revenues:
Total revenues	191,733	195,515
Operating Segments [Member] | Government Systems [Member] | Service [Member]
Revenues:
Total revenues	80,414	65,827
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (5,929)	$ (1,558)