Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017
Accounts receivable, net:
Accounts receivable, Billed	$ 115,662	$ 145,626
Accounts receivable, Unbilled	101,564	119,565
Allowance for doubtful accounts	(2,173)	(1,470)
Accounts receivable, net	215,053	263,721
Inventories:
Raw materials	62,503	56,096
Work in process	35,846	25,820
Finished goods	79,594	81,285
Inventories	177,943	163,201
Prepaid expenses and other current assets:
Prepaid expenses	56,751	51,856
Other	9,443	5,980
Prepaid expenses and other current assets	66,194	57,836
Other acquired intangible assets, net:
Other acquired intangible assets, gross	216,730	215,091
Less: accumulated amortization	(177,233)	(173,414)
Other acquired intangible assets, net	39,497	41,677
Other assets:
Investment in unconsolidated affiliate	144,289	141,894
Deferred income taxes	200,880	134,764
Capitalized software costs, net	211,766	203,686
Patents, orbital slots and other licenses, net	16,400	16,500
Other	32,193	32,522
Other assets	605,528	529,366
Accrued liabilities:
Collections in excess of revenues and deferred revenues	89,129	76,682
Accrued employee compensation	23,472	41,691
Accrued vacation	34,759	33,214
Warranty reserve, current portion	7,168	7,796
Other	49,703	65,576
Accrued liabilities	204,231	224,959
Other liabilities:
Deferred revenue, long-term portion	68,358	4,617
Deferred rent, long-term portion	11,839	10,743
Warranty reserve, long-term portion	2,635	3,262
Satellite performance incentives obligation, long-term portion	18,940	19,164
Deferred income taxes, long-term	513	1,936
Other	7,605	3,000
Other liabilities	109,890	42,722
Technology [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	88,827	87,592
Contracts and Customer Relationships [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	103,346	103,034
Satellite Co-Location Rights [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	8,600	8,600
Trade Name [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	5,940	5,940
Other [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	10,017	9,925
Satellites, Net [Member]
Property and equipment, net:
Property and equipment	1,473,379	1,434,824
Less accumulated depreciation and amortization	(339,241)	(326,554)
Property and equipment, net	1,134,138	1,108,270
Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	1,248,528	1,202,589
Less accumulated depreciation and amortization	(689,142)	(661,981)
Property and equipment, net	559,386	540,608
Satellites [Member] | Satellites, Net [Member]
Property and equipment, net:
Property and equipment	559,380	559,380
Capital Lease of Satellite Capacity - Anik F2 [Member] | Satellites, Net [Member]
Property and equipment, net:
Property and equipment	99,090	99,090
Construction in Progress [Member] | Satellites, Net [Member]
Property and equipment, net:
Property and equipment	814,909	776,354
Construction in Progress [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	131,653	116,902
Equipment and Software [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	707,190	679,008
CPE Leased Equipment [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	266,190	271,917
Less accumulated depreciation and amortization	(160,800)	(158,200)
Furniture and Fixtures [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	32,424	30,539
Leasehold Improvements [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	87,575	80,727
Building [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	8,923	8,923
Land [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	$ 14,573	$ 14,573