Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Fair value of financial and nonfinancial obligations.

+ References

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Definition

Year which long-term purchase commitment is set to expire, in CCYY format, for example, ‘2020’ represents the commitment expires in fiscal year 2020.

+ References

No definition available.

+ Details

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Namespace Prefix:	vsat_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate carrying amount of satellite performance incentives obligation as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	vsat_
Data Type:	xbrli:monetaryItemType
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Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Satellite Performance Incentives Obligation [Member] \| ViaSat-1 and ViaSat-2 Satellites [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Expiration year of in-orbit satellite performance incentive obligation	2028
2025 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of senior notes issued	$ 700,000,000		$ 700,000,000
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on a recurring basis	0
Liabilities measured at fair value on a recurring basis		$ 0
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Satellite Performance Incentives Obligation [Member] \| ViaSat-1 and ViaSat-2 Satellites [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Satellite performance incentives obligation	33,500,000	21,000,000
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| 2025 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	662,600,000	674,000,000
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Ex-Im Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	$ 292,500,000	$ 347,400,000