Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Sep. 30, 2025	Mar. 31, 2025
Accounts receivable, net:
Accounts receivable, Billed	$ 528,343	$ 539,522
Accounts receivable, Unbilled	175,829	180,871
Allowance for doubtful accounts	(21,352)	(20,841)
Accounts receivable, net	682,820	699,552
Inventories:
Raw materials	99,904	96,893
Work in process	16,495	19,761
Finished goods	162,259	177,289
Inventories	278,658	293,943
Prepaid expenses and other current assets:
Prepaid expenses	160,295	176,694
Other	83,528	105,649
Prepaid expenses and other current assets	243,823	282,343
Property, equipment and satellites, net:
Property, equipment and satellites, gross	11,811,284	11,440,273
Less: accumulated depreciation and amortization	(4,526,027)	(4,034,609)
Property and equipment, net	7,285,257	7,405,664
Acquired intangible assets, net:
Acquired intangible assets, gross	2,879,380	2,904,049
Less: accumulated amortization	(752,484)	(633,272)
Acquired intangible assets, net	2,126,896	2,270,777
Other assets:
Deferred income taxes	136,546	160,452
Capitalized software costs, net	282,422	264,492
Patents, orbital slots and other licenses, net	125,832	119,193
Other	312,771	301,641
Other assets	857,571	845,778
Accrued and other liabilities:
Collections in excess of revenues and deferred revenues	288,357	294,034
Accrued employee compensation	110,021	185,556
Accrued vacation	47,088	46,651
Operating lease liabilities	$ 67,591	$ 65,310
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued and other liabilities	Accrued and other liabilities
Interest payable	$ 50,008	$ 52,183
Other	251,035	264,795
Accrued and other liabilities	814,100	908,529
Other liabilities:
Deferred revenues, long-term portion	777,631	786,710
Deferred income taxes	963,978	1,069,717
Other	307,781	324,726
Other liabilities	2,049,390	2,181,153
Contracts and Customer Relationships [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	1,433,184	1,432,562
Orbital Slots And Spectrum Assets [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	1,088,600	1,088,600
Technology [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	224,394	247,921
Trade Names [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	114,587	116,949
Other [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	18,615	18,017
Equipment and Software [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	4,012,660	3,837,083
CPE Leased Equipment [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, cost	527,085	525,972
Furniture and Fixtures [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	56,449	58,153
Leasehold Improvements [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	318,656	313,249
Buildings [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	15,388	15,388
Land [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	19,661	19,661
Construction in Progress [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	730,119	722,194
Satellites [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	3,412,688	3,405,067
Satellite Ka-band Capacity Obtained under Finance Leases [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	338,201	338,201
Satellites under Construction [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	$ 2,380,377	$ 2,205,305