Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018
Accounts receivable, net:
Accounts receivable, Billed	$ 156,860	$ 184,536
Accounts receivable, Unbilled	80,852	85,156
Allowance for doubtful accounts	(1,627)	(2,027)
Accounts receivable, net	236,085	267,665
Inventories:
Raw materials	71,901	62,252
Work in process	47,756	47,465
Finished goods	100,361	86,590
Inventories	220,018	196,307
Prepaid expenses and other current assets:
Prepaid expenses	87,019	68,516
Other	15,958	8,619
Prepaid expenses and other current assets	102,977	77,135
Other acquired intangible assets, net:
Other acquired intangible assets, gross	217,233	219,137
Less: accumulated amortization	(188,675)	(187,275)
Other acquired intangible assets, net	28,558	31,862
Other assets:
Investment in unconsolidated affiliate	169,454	163,835
Deferred income taxes	242,894	222,274
Capitalized software costs, net	246,788	246,792
Patents, orbital slots and other licenses, net	17,000	16,100
Other	66,022	37,133
Other assets	742,158	686,134
Accrued liabilities:
Collections in excess of revenues and deferred revenues	115,579	121,439
Accrued employee compensation	27,133	46,106
Accrued vacation	40,710	39,022
Warranty reserve, current portion	4,935	5,357
Other	63,955	51,752
Accrued liabilities	252,312	263,676
Other liabilities:
Deferred revenues, long-term portion	81,573	77,831
Deferred rent, long-term portion	14,391	13,769
Warranty reserve, long-term portion	1,540	1,557
Satellite performance incentive obligations, long-term portion	25,670	18,181
Other	9,086	9,902
Other liabilities	132,260	121,240
Technology [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	89,204	90,652
Contracts and Customer Relationships [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	103,449	103,808
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	10,040	10,137
Satellites, Net [Member]
Property and equipment, net:
Property and equipment	1,661,446	1,613,935
Less: accumulated depreciation and amortization	(396,425)	(373,948)
Property and equipment, net	1,265,021	1,239,987
Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	1,521,337	1,442,398
Less: accumulated depreciation and amortization	(749,130)	(719,910)
Property and equipment, net	772,207	722,488
Satellites [Member] | Satellites, Net [Member]
Property and equipment, net:
Property and equipment	1,160,593	1,152,503
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	401,763	362,342
Construction in Progress [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	135,560	108,192
Equipment and Software [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	899,685	864,140
CPE Leased Equipment [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	310,506	298,746
Less: accumulated depreciation and amortization	(130,100)	(129,000)
Furniture and Fixtures [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	37,580	35,234
Leasehold Improvements [Member] | Property and Equipment, Net [Member]
Property and equipment, net:
Property and equipment	113,761	111,841
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	$ 15,322	$ 15,322