Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Product revenues	$ 166,118	$ 160,676
Service revenues	213,926	202,454
Total revenues	380,044	363,130
Operating profits (losses):
(Loss) income from operations	(17,950)	7,778
Amortization of acquired intangible assets	(3,260)	(2,513)
Operating Segments [Member]
Operating profits (losses):
(Loss) income from operations	(14,690)	10,291
Operating Segments [Member] | Satellite Services [Member]
Revenues:
Product revenues	217	6,685
Service revenues	151,997	145,708
Total revenues	152,214	152,393
Operating profits (losses):
(Loss) income from operations	18,843	30,867
Amortization of acquired intangible assets	(2,093)	(1,104)
Operating Segments [Member] | Commercial Networks [Member]
Revenues:
Product revenues	36,483	58,596
Service revenues	8,765	6,957
Total revenues	45,248	65,553
Operating profits (losses):
(Loss) income from operations	(66,125)	(38,531)
Amortization of acquired intangible assets	(407)	(445)
Operating Segments [Member] | Government Systems [Member]
Revenues:
Product revenues	129,418	95,395
Service revenues	53,164	49,789
Total revenues	182,582	145,184
Operating profits (losses):
(Loss) income from operations	32,592	17,955
Amortization of acquired intangible assets	(760)	(964)
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (3,260)	$ (2,513)