Segment Information - Segment Revenues, Expenses and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024
Revenues:
Total revenues		$ 1,157,045	$ 1,123,767	$ 3,468,992	$ 3,372,489
Operating Expenses [Abstract]
Depreciation				771,528	779,675
Stock-based compensation expense				58,928	63,468
Total expenses		1,065,905	1,036,672	3,164,595	3,118,098
Operating profits (losses):
Amortization of acquired intangible assets		(64,838)	(65,847)	(195,648)	(198,086)
Interest income		165,590	17,708	192,405	64,396
Interest expense		(87,478)	(94,476)	(281,322)	(315,592)
(Loss) gain on extinguishment of debt, net		(11,647)	(96,614)	(11,935)	(99,814)
Other income (expense), net		114	(9,976)	(5,050)	(9,976)
Income (loss) before income taxes		92,881	(162,110)	2,847	(304,681)
Income (loss) from operations		26,302	21,248	108,749	56,305
Product [Member]
Revenues:
Total revenues		334,227	314,397	998,294	944,084
Service [Member]
Revenues:
Total revenues		822,818	809,370	2,470,698	2,428,405
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations		91,140	87,095	304,397	254,391
Operating Segments [Member] | Communication Services [Member]
Revenues:
Total revenues		825,342	820,347	2,489,368	2,473,519
Operating Expenses [Abstract]
Depreciation		248,673	244,673	735,641	744,136
Stock-based compensation expense		14,388	12,884	35,190	38,462
Other than acquired intangible assets amortization	[1]	9,175	10,289	27,923	31,998
Acquisition and transaction related expenses		4,840	14,061	16,194	45,532
Other segment items	[2]	510,238	494,083	1,524,131	1,527,562
Total expenses	[3]	787,314	775,990	2,339,079	2,387,690
Operating profits (losses):
Income (loss) from operations		38,028	44,357	150,289	85,829
Operating Segments [Member] | Communication Services [Member] | Government Satcom Services [Member]
Revenues:
Total revenues		202,369	195,048	589,937	558,796
Operating Segments [Member] | Communication Services [Member] | Aviation Services [Member]
Revenues:
Total revenues		303,693	263,880	897,317	783,022
Operating Segments [Member] | Communication Services [Member] | Maritime Services [Member]
Revenues:
Total revenues		114,949	118,895	350,344	364,021
Operating Segments [Member] | Communication Services [Member] | Fixed Services and Other Services [Member]
Revenues:
Total revenues		144,565	181,162	474,993	567,651
Operating Segments [Member] | Communication Services [Member] | Product [Member]
Revenues:
Total revenues		59,766	61,362	176,777	200,029
Operating Segments [Member] | Communication Services [Member] | Service [Member]
Revenues:
Total revenues		765,576	758,985	2,312,591	2,273,490
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Revenues:
Total revenues		331,703	303,420	979,624	898,970
Operating Expenses [Abstract]
Depreciation		12,484	12,401	35,887	35,539
Stock-based compensation expense		9,711	8,619	23,738	25,006
Other than acquired intangible assets amortization	[1]	5,190	4,545	16,733	13,866
Acquisition and transaction related expenses		685	6,794	4,136	12,174
Other segment items	[2]	250,521	228,323	745,022	643,823
Total expenses	[3]	278,591	260,682	825,516	730,408
Operating profits (losses):
Income (loss) from operations		53,112	42,738	154,108	168,562
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Information Security and Cyber Defense Products [Member]
Revenues:
Total revenues		96,954	89,497	294,030	228,552
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Space and Mission Systems Products [Member]
Revenues:
Total revenues		77,490	77,752	243,694	229,840
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Tactical Networking Products [Member]
Revenues:
Total revenues		93,900	78,528	236,372	229,972
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Advanced Technologies and Other Products [Member]
Revenues:
Total revenues		6,117	7,258	47,421	55,691
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Product [Member]
Revenues:
Total revenues		274,461	253,035	821,517	744,055
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Service [Member]
Revenues:
Total revenues		57,242	50,385	158,107	154,915
Corporate, Non-Segment [Member]
Operating profits (losses):
Amortization of acquired intangible assets		(64,838)	(65,847)	(195,648)	(198,086)
Interest income		165,590	17,708	192,405	64,396
Interest expense		(87,478)	(94,476)	(281,322)	(315,592)
(Loss) gain on extinguishment of debt, net		(11,647)	(96,614)	(11,935)	(99,814)
Other income (expense), net		$ 114	$ (9,976)	$ (5,050)	$ (9,976)

[1] Including amortization of capitalized cloud computing implementation costs.

[2] Other segment items include operating expenses such as cost of service and product revenues, selling, general and administrative expenses, IR&D expenses and related activities excluding allocable portion of depreciation, other than acquired intangibles amortization, stock-based compensation, and certain significant items that are disclosed under each segment.

[3] For the three and nine months ended December 31, 2025, IR&D expense and related activities, including allocable depreciation, stock-based compensation and other expenses were $26.7 million and $67.5 million, respectively, for the communication services segment, and $20.2 million and $55.9 million, respectively, for the defense and advanced technologies segment. For the three and nine months ended December 31, 2024, IR&D expense and related activities, including allocable depreciation, stock-based compensation and other expenses were $21.5 million and $66.9 million, respectively, for the communication services segment, and $15.2 million and $41.7 million, respectively, for the defense and advanced technologies segment.