Segment Information - Segment Revenues, Expenses and Operating Profits (Losses) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Independent research and development	$ 42,263	$ 33,390	$ 76,456	$ 71,953
Communication Services [Member]
Segment Reporting Information [Line Items]
Independent research and development	21,700	19,700	40,800	45,500
Defense and Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Independent research and development	$ 20,600	$ 13,700	$ 35,600	$ 26,500