Basis of Presentation - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2023	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2024 USD ($) Segment shares	Sep. 30, 2023 USD ($) shares	Mar. 31, 2024 USD ($) shares
Company And Summary Of Significant Accounting Policies [Line Items]
Revenue, practical expedient, financing component				true
Remaining performance obligations		$ 3,700,000,000		$ 3,700,000,000
Number of reportable segments | Segment				2
Increase in collections in excess of revenues and deferred revenues				$ 34,100,000
Collections in excess of revenues and deferred revenues, recognized revenue		39,900,000	$ 23,400,000	146,200,000	$ 77,200,000
Capitalized interest expense		48,600,000	70,200,000	$ 105,200,000	126,900,000
Operating lease, existence of option to terminate				true
Operating lease, option to terminate, description				some of which include renewal options, and some of which include options to terminate the leases within one year.
Total capitalized costs related to patents		4,000,000		$ 4,000,000		$ 3,900,000
Total capitalized costs related to orbital slots and other licenses		122,400,000		122,400,000		117,000,000
Accumulated amortization of patents, orbital slots and other licenses		9,300,000		9,300,000		8,400,000
Debt issuance costs capitalized				35,600,000	50,100,000
Self-insurance liability		6,000,000		6,000,000		6,500,000
Repurchase and immediate retirement of treasury shares pursuant to vesting of certain RSU agreements | value		980,000	353,000	2,395,000	2,565,000
Stock-based compensation expense		22,800,000	21,700,000	41,965,000	43,470,000
Insurance claim receivables		64,000,000		$ 64,000,000		261,500,000
Accounting Standards Update 2022-03 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In June 2022, the FASB issued ASU 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. ASU 2022-03 clarifies that a contractual restriction on the sale of an equity security is not considered in measuring the security's fair value. The standard also requires certain disclosures for equity securities that are subject to contractual restrictions. The Company adopted the new guidance in the first quarter of fiscal year 2025 and the guidance did not have a material impact on its consolidated financial statements and disclosures.
Accounting Standards Update 2023-01 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In March 2023, the FASB issued ASU 2023-01, Leases (Topic 842) – Common Control Agreements. The amendments in this update that apply to public business entities clarify the accounting for leasehold improvements associated with common control leases. The Company adopted the new guidance in the first quarter of fiscal year 2025 and the guidance did not have a material impact on its consolidated financial statements and disclosures.
Accounting Standards Update 2023-06 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative. This ASU amends certain disclosure and presentation requirements for a variety of topics within the FASB ASC. These amendments will also align the requirements in the ASC with the SEC's regulations. The effective date for each amended topic in the ASC is the date on which the SEC’s removal of the related disclosure requirement from Regulation S-X or Regulation S-K becomes effective, and will not be effective if the SEC has not removed the applicable disclosure requirements by June 30, 2027. Early adoption is prohibited. The Company is currently evaluating the impact of this standard on its consolidated financial statements and disclosures.
Accounting Standards Update 2023-07 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This ASU requires public entities to enhance disclosures about their reportable segments' significant expenses on an interim and annual basis. The new standard will become effective for the Company's annual disclosures beginning in fiscal year 2025 and for interim disclosures beginning in fiscal year 2026 on a retrospective basis. Early adoption is permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements and disclosures.
Accounting Standards Update 2023-09 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 enhances income tax disclosures by requiring disclosure of specific categories in the income tax rate reconciliation table and disaggregation of income taxes paid. The new standard will become effective for the Company beginning in fiscal year 2026. Early adoption is permitted and the new standard should be applied prospectively, however retrospective application is permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statement disclosures.
Accounting Standards Update 2024-02 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In March 2024, the FASB issued ASU 2024-02, Codification Improvements – Amendments to Remove References to the Concepts Statements. This update contains amendments to the Codification that remove references to various Concepts Statements. The amendments in this update are not intended to result in significant accounting changes for most entities. The amendments in this update are effective for the Company beginning in fiscal year 2026. Early adoption is permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements and disclosures.
Accounting Standards Update 2024-03 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements				In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This ASU requires additional disclosures about certain categories of costs and expenses in the notes to financial statements. The new standard will become effective for the Company’s annual disclosures beginning in fiscal year 2028 and for interim disclosures beginning in fiscal year 2029. Early adoption is permitted and the amendments should be applied either prospectively to financial statements issued for reporting periods after the effective date of the ASU or retrospectively to any or all periods presented in the financial statements. The Company is currently evaluating the impact of this standard on its consolidated financial statements and disclosures.
CPE Leased Equipment [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, cost		540,784,000		$ 540,784,000		567,548,000
Accumulated depreciation and amortization		302,000,000		302,000,000		267,400,000
ViaSat-3 F1 satellite [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Maximum expected recovery % of the planned throughput	10.00%
Satellites [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Reduction to carrying value including capitalized interest			1,670,000,000		1,670,000,000
Insurance claim receivables			$ 770,000,000		$ 770,000,000
Unfavorable Regulatory Action [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Accrued reserves		11,400,000		11,400,000		16,600,000
Indemnification Guarantee [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Accrued reserves		$ 0		$ 0		$ 0
Common Stock [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Common stock issued based on the vesting terms of certain restricted stock unit agreements | shares		150,045	57,027	370,158	194,496
Common Stock Held in Treasury [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Shares of common stock outstanding | shares		0		0		0
Repurchase and immediate retirement of treasury shares pursuant to vesting of certain RSU agreements, shares | shares		56,243	12,551	141,881	61,401
Repurchase and immediate retirement of treasury shares pursuant to vesting of certain RSU agreements | value		$ 1,000,000		$ 2,400,000	$ 2,600,000