Segment Information - Other Acquired Intangible Assets, Net, Goodwill Included in Segment Assets and Depreciation and Amortization of Acquired Intangible Assets by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Mar. 31, 2024
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	$ 2,410,852		$ 2,410,852		$ 2,544,467
Goodwill	1,623,760		1,623,760		1,621,763
Depreciation and amortization of intangible assets	354,666	$ 333,765	685,870	$ 508,344
Operating Segments [Member] | Communication Services [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net	2,410,852		2,410,852		2,544,315
Goodwill	1,583,374		1,583,374		1,581,937
Depreciation and amortization of intangible assets	272,039	238,681	521,172	373,464
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Other acquired intangible assets, net					152
Goodwill	40,386		40,386		$ 39,826
Depreciation and amortization of intangible assets	16,603	13,710	32,459	25,695
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization of intangible assets	$ 66,024	$ 81,374	$ 132,239	$ 109,185