Basis of Presentation - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Jun. 30, 2025 USD ($) shares	Jun. 30, 2025 USD ($) Segment shares	Jun. 30, 2024 USD ($) shares	Mar. 31, 2025 USD ($) shares	Mar. 31, 2024 USD ($)
Company And Summary Of Significant Accounting Policies [Line Items]
Revenue, practical expedient, financing component		true
Cash dividends	$ 155,700,000
Company's share of dividend		$ 96,000,000
Reduction to noncontrolling interest		59,695,000
Distributions to minority shareholders		45,902,000	$ 0
Remaining performance obligations	3,500,000,000	$ 3,500,000,000
Number of reportable segments | Segment		2
Increase in collections in excess of revenues and deferred revenues		$ 4,800,000
Collections in excess of revenues and deferred revenues, recognized revenue		106,100,000	106,300,000
Capitalized interest expense		$ 55,200,000	56,600,000
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	139,600,000	$ 139,600,000		$ 129,400,000
Accumulated amortization of patents, orbital slots and other licenses	13,400,000	13,400,000		10,200,000
Patents, orbital slots and other licenses amortization expense		3,200,000
Debt issuance costs capitalized		0	0
Self-insurance liability	5,500,000	5,500,000		5,900,000
Repurchase and immediate retirement of treasury shares pursuant to vesting of certain RSU agreements | value		4,668,000	1,415,000
Stock-based compensation expense		14,707,000	19,182,000
Continuing Operations [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Stock-based compensation expense		$ 14,700,000	$ 19,200,000
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 Company adopted the new guidance for annual disclosures in fiscal year 2025 and for interim disclosures in the first quarter of fiscal year 2026 on a retrospective basis. See Note 10 — Segment Information for additional information.
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 annual 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's annual disclosures 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 statements and 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 Company adopted the new guidance on a prospective basis in the first quarter of fiscal year 2026 and the guidance did not have an impact 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. As clarified in ASU 2025-01, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date, 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.
Accounting Standards Update 2025-04 [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Description of new accounting pronouncements		In May 2025, the FASB issued ASU 2025-04, Compensation – Stock Compensation (Topic 718) and Revenue from Contracts with Customers (Topic 606): Clarifications to Share-Based Consideration Payable to a Customer. The purpose of this ASU is to reduce diversity in practice and improve the decision usefulness and operability of the guidance for share-based consideration payable to a customer in conjunction with selling goods or services. The new standard will become effective for the Company's interim and annual disclosures beginning in fiscal year 2028. Early adoption is permitted and the new guidance can be applied either on a modified retrospective or a retrospective basis. 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	524,974,000	$ 524,974,000		525,972,000
Accumulated depreciation and amortization	335,600,000	335,600,000		328,000,000
Satellites [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Reduction to carrying value including capitalized interest					$ 1,670,000,000
Insurance claim receivables					$ 770,000,000
Accrued and Other Liabilities [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Dividends payable	13,800,000	13,800,000
Unfavorable Regulatory Action [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Accrued reserves	15,100,000	15,100,000		14,800,000
Unfavorable Regulatory Action [Member] | Performance Obligations [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Accrued reserves	15,100,000	15,100,000		14,800,000
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		1,351,971	220,113
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		503,164	85,638
Repurchase and immediate retirement of treasury shares pursuant to vesting of certain RSU agreements | value		$ 4,700,000	$ 1,400,000