Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Accounts receivable, net:
Accounts receivable, Billed	$ 145,323	$ 260,431
Accounts receivable, Unbilled	60,951	75,661
Allowance for doubtful accounts	(3,482)	(5,394)
Accounts receivable, net	202,792	330,698
Inventories:
Raw materials	95,872	83,353
Work in process	68,071	59,429
Finished goods	170,976	151,634
Inventories	334,919	294,416
Prepaid expenses and other current assets:
Prepaid expenses	82,455	84,872
Other	30,093	31,409
Prepaid expenses and other current assets	112,548	116,281
Property, equipment and satellites, net:
Property, equipment and satellites, gross	4,686,060	4,101,634
Less: accumulated depreciation and amortization	(1,712,327)	(1,514,899)
Property and equipment, net	2,973,733	2,586,735
Other acquired intangible assets, net:
Other acquired intangible assets, gross	216,489	213,281
Less: accumulated amortization	(205,410)	(198,842)
Other acquired intangible assets, net	11,079	14,439
Other assets:
Investment in unconsolidated affiliate	168,787	160,204
Deferred income taxes	277,734	276,331
Capitalized software costs, net	239,104	242,741
Patents, orbital slots and other licenses, net	53,058	39,135
Other	104,094	88,941
Other assets	842,777	807,352
Accrued and other liabilities:
Collections in excess of revenues and deferred revenues	206,807	123,019
Accrued employee compensation	61,479	72,654
Accrued vacation	53,758	48,963
Warranty reserve, current portion	6,115	6,233
Operating lease liabilities	$ 49,370	$ 42,146
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	vsat:AccruedAndOtherLiabilitiesCurrent	vsat:AccruedAndOtherLiabilitiesCurrent
Other	$ 108,036	$ 98,175
Accrued and other liabilities	485,565	391,190
Other liabilities:
Deferred revenues, long-term portion	97,485	80,802
Warranty reserve, long-term portion	5,766	5,410
Satellite performance incentive obligations, long-term portion	23,005	24,349
Other	25,784	10,373
Other liabilities	152,040	120,934
Technology [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	91,804	89,228
Contracts and Customer Relationships [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	103,724	103,114
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	6,421	6,399
Satellites [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	969,952	969,952
Satellites under Construction [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	1,264,177	906,720
Equipment and Software [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	1,424,548	1,229,926
CPE Leased Equipment [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	410,879	399,343
Less: accumulated depreciation and amortization	(186,800)	(165,700)
Satellite Ka-band Capacity Obtained under Finance Leases [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	173,322	171,801
Furniture and Fixtures [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	57,582	54,688
Leasehold Improvements [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	144,214	137,287
Building [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	8,923	8,923
Land [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	2,291	2,291
Construction in Progress [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	$ 230,172	$ 220,703