Segment Information - Segment Revenues and Operating Profits (Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Revenues:
Total revenues	$ 1,123,767	$ 1,128,539	$ 3,372,489	$ 3,133,745
Operating profits (losses):
Income (loss) from operations	21,248	(43,918)	56,305	(890,101)
Amortization of acquired intangible assets	(65,847)	(91,719)	(198,086)	(200,904)
Product [Member]
Revenues:
Total revenues	314,397	303,073	944,084	941,174
Service [Member]
Revenues:
Total revenues	809,370	825,466	2,428,405	2,192,571
Operating Segments [Member]
Operating profits (losses):
Income (loss) from operations	87,095	47,801	254,391	(689,197)
Operating Segments [Member] | Communication Services [Member]
Revenues:
Total revenues	820,347	874,858	2,473,519	2,281,675
Operating profits (losses):
Income (loss) from operations	44,357	36,049	85,829	(805,080)
Operating Segments [Member] | Communication Services [Member] | Government Satcom Services [Member]
Revenues:
Total revenues	195,048	176,311	558,796	428,778
Operating Segments [Member] | Communication Services [Member] | Aviation Services [Member]
Revenues:
Total revenues	263,880	236,008	783,022	611,169
Operating Segments [Member] | Communication Services [Member] | Maritime Services [Member]
Revenues:
Total revenues	118,895	130,121	364,021	305,894
Operating Segments [Member] | Communication Services [Member] | Fixed Services and Other Services [Member]
Revenues:
Total revenues	181,162	229,929	567,651	691,063
Operating Segments [Member] | Communication Services [Member] | Product [Member]
Revenues:
Total revenues	61,362	102,489	200,029	244,771
Operating Segments [Member] | Communication Services [Member] | Service [Member]
Revenues:
Total revenues	758,985	772,369	2,273,490	2,036,904
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Revenues:
Total revenues	303,420	253,681	898,970	852,070
Operating profits (losses):
Income (loss) from operations	42,738	11,752	168,562	115,883
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Information Security and Cyber Defense Products [Member]
Revenues:
Total revenues	89,497	72,115	228,552	211,169
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Space and Mission Systems Products [Member]
Revenues:
Total revenues	77,752	65,182	229,840	229,875
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Tactical Networking Products [Member]
Revenues:
Total revenues	78,528	57,676	229,972	137,505
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Advanced Technologies and Other Products [Member]
Revenues:
Total revenues	7,258	5,611	55,691	117,854
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Product [Member]
Revenues:
Total revenues	253,035	200,584	744,055	696,403
Operating Segments [Member] | Defense and Advanced Technologies [Member] | Service [Member]
Revenues:
Total revenues	50,385	53,097	154,915	155,667
Material Reconciling Items [Member]
Operating profits (losses):
Amortization of acquired intangible assets	$ (65,847)	$ (91,719)	$ (198,086)	$ (200,904)