Segment Information - Other Acquired Intangible Assets, Net and Goodwill Included in Segment Assets and Amortization of Acquired Intangible Assets by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2016
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	$ 31,039		$ 33,604
Goodwill	116,560		117,040
Amortization of acquired intangible assets	2,513	$ 4,810
Operating Segments [Member] | Satellite Services [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	7,646		8,751
Goodwill	9,809		9,809
Amortization of acquired intangible assets	1,104	2,765
Operating Segments [Member] | Commercial Networks [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	6,137		6,581
Goodwill	43,956		43,990
Amortization of acquired intangible assets	445	496
Operating Segments [Member] | Government Systems [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	17,256		18,272
Goodwill	62,795		$ 63,241
Amortization of acquired intangible assets	$ 964	$ 1,549