Employee Benefits - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Number of common stock that would be issued based on year-end common stock closing price	294,507
Discretionary contributions accrued by the Company under voluntary deferred compensation plan under Section 401(k) of the Internal Revenue Code	$ 19.4	$ 16.8

The estimated number of shares that would be issued based on the year-end common stock closing price in order to settle the Company's discretionary contributions under a defined contribution plan under Section 401(k).

No definition available.

Name:	vsat_EstimatedNumberOfSharesToBeIssuedToSettleCertainAccruedEmployeeCompensationLiabilities
Namespace Prefix:	vsat_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant