Commitments - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended
	Apr. 30, 2017	Jul. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Long-term Purchase Commitment [Line Items]
Satellite performance incentives obligation, Noncurrent			$ 18,181,000	$ 19,164,000
Description of operating lease arrangements			The Company leases office and other facilities under non-cancelable operating leases with initial terms ranging from one to 15 years which expire between fiscal year 2019 and fiscal year 2030 and provide for pre-negotiated fixed rental rates during the terms of the lease. Certain of the Company’s facilities leases contain option provisions which allow for extension of the lease terms.
Non-cancelable operating leases initial term			10 years
Rent expense			$ 41,200,000	$ 34,000,000	$ 27,700,000
Minimum [Member]
Long-term Purchase Commitment [Line Items]
Non-cancelable operating leases initial term			1 year
Maximum [Member]
Long-term Purchase Commitment [Line Items]
Non-cancelable operating leases initial term			15 years
Satellite Capacity Agreements [Member]
Long-term Purchase Commitment [Line Items]
Future minimum payments on purchase commitments for fiscal year 2019			$ 49,400,000
Future minimum payments on purchase commitments for fiscal year 2020			56,600,000
Future minimum payments on purchase commitments for fiscal year 2021			43,300,000
Future minimum payments on purchase commitments for fiscal year 2022			19,300,000
Future minimum payments on purchase commitments for fiscal year 2023			13,300,000
Future minimum payments on purchase commitments thereafter			0
ViaSat-1 Satellite [Member]
Long-term Purchase Commitment [Line Items]
Satellite performance incentives obligation			21,000,000
Satellite performance incentives obligation, current			2,800,000
Satellite performance incentives obligation, Noncurrent			$ 18,200,000
ViaSat-1 Satellite [Member] | Satellite Performance Incentives Obligation [Member]
Long-term Purchase Commitment [Line Items]
Period of in-orbit satellite performance incentive payments			15 years
Commitment amount			$ 28,500,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2019			2,500,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2020			2,600,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2021			2,800,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2022			3,000,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2023			3,300,000
Future minimum payments under satellite performance incentives obligation thereafter			$ 14,300,000
Satellite - ViaSat-2 [Member] | Satellite Performance Incentives Obligation [Member]
Long-term Purchase Commitment [Line Items]
Period of in-orbit satellite performance incentive payments	9 years
Commitment amount	$ 21,000,000
ViaSat-3 Class Satellites [Member] | Capital Addition [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount		$ 379,500,000