Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Total revenues	$ 719,717	$ 575,559	$ 2,085,931	$ 1,660,325
Operating profits (losses):
Income (loss) from operations	4,527	21,760	29,117	29,129
Amortization of acquired intangible assets	(7,531)	(1,313)	(20,859)	(4,171)
Product [Member]
Revenues:
Total revenues	316,143	266,514	918,073	773,128
Service [Member]
Revenues:
Total revenues	403,574	309,045	1,167,858	887,197
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations	12,058	23,073	49,976	33,300
Operating Segments [Member] | Satellite Services [Member]
Revenues:
Total revenues	309,711	220,789	883,938	638,660
Operating profits (losses):
Income (loss) from operations	14,152	11,457	43,711	21,083
Amortization of acquired intangible assets	(7,231)	(557)	(19,650)	(1,612)
Operating Segments [Member] | Satellite Services [Member] | Service [Member]
Revenues:
Total revenues	309,711	220,789	883,938	638,660
Operating Segments [Member] | Commercial Networks [Member]
Revenues:
Total revenues	139,677	90,099	393,079	236,121
Operating profits (losses):
Income (loss) from operations	(44,572)	(39,028)	(127,601)	(135,785)
Amortization of acquired intangible assets				(257)
Operating Segments [Member] | Commercial Networks [Member] | Product [Member]
Revenues:
Total revenues	123,059	75,690	343,525	197,560
Operating Segments [Member] | Commercial Networks [Member] | Service [Member]
Revenues:
Total revenues	16,618	14,409	49,554	38,561
Operating Segments [Member] | Government Systems [Member]
Revenues:
Total revenues	270,329	264,671	808,914	785,544
Operating profits (losses):
Income (loss) from operations	42,478	50,644	133,866	148,002
Amortization of acquired intangible assets	(300)	(756)	(1,209)	(2,302)
Operating Segments [Member] | Government Systems [Member] | Product [Member]
Revenues:
Total revenues	193,084	190,824	574,548	575,568
Operating Segments [Member] | Government Systems [Member] | Service [Member]
Revenues:
Total revenues	77,245	73,847	234,366	209,976
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (7,531)	$ (1,313)	$ (20,859)	$ (4,171)