Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Mar. 31, 2025
Accounts receivable, net:
Accounts receivable, Billed	$ 542,120	$ 539,522
Accounts receivable, Unbilled	227,751	180,871
Allowance for doubtful accounts	(20,476)	(20,841)
Accounts receivable, net	749,395	699,552
Inventories:
Raw materials	110,955	96,893
Work in process	16,977	19,761
Finished goods	159,022	177,289
Inventories	286,954	293,943
Prepaid expenses and other current assets:
Prepaid expenses	174,854	176,694
Other	91,570	105,649
Prepaid expenses and other current assets	266,424	282,343
Property, equipment and satellites, net:
Property, equipment and satellites, gross	12,056,904	11,440,273
Less: accumulated depreciation and amortization	(4,757,439)	(4,034,609)
Property and equipment, net	7,299,465	7,405,664
Acquired intangible assets, net:
Acquired intangible assets, gross	2,879,366	2,904,049
Less: accumulated amortization	(817,508)	(633,272)
Acquired intangible assets, net	2,061,858	2,270,777
Other assets:
Deferred income taxes	107,242	160,452
Capitalized software costs, net	301,544	264,492
Patents, orbital slots and other licenses, net	123,559	119,193
Other	311,395	301,641
Other assets	843,740	845,778
Accrued and other liabilities:
Collections in excess of revenues and deferred revenues	294,152	294,034
Accrued employee compensation	147,340	185,556
Accrued vacation	43,038	46,651
Operating lease liabilities	$ 68,856	$ 65,310
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued and other liabilities	Accrued and other liabilities
Interest payable	$ 78,037	$ 52,183
Other	268,132	264,795
Accrued and other liabilities	899,555	908,529
Other liabilities:
Deferred revenues, long-term portion	1,078,238	786,710
Deferred income taxes	986,612	1,069,717
Other	292,469	324,726
Other liabilities	2,357,319	2,181,153
Contracts and Customer Relationships [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	1,433,006	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	224,488	247,921
Trade Names [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	114,590	116,949
Other [Member]
Acquired intangible assets, net:
Acquired intangible assets, gross	18,682	18,017
Equipment and Software [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	4,094,183	3,837,083
CPE Leased Equipment [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, cost	525,057	525,972
Furniture and Fixtures [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	54,143	58,153
Leasehold Improvements [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	318,913	313,249
Buildings [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	15,352	15,388
Land [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	11,251	19,661
Construction in Progress [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	750,826	722,194
Satellites [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	3,412,988	3,405,067
Satellite Ka-band Capacity Obtained under Finance Leases [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	339,351	338,201
Satellites under Construction [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	$ 2,534,840	$ 2,205,305