Segment Information - Segment Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 16,087,869	$ 16,329,364
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,120,182	5,160,985
Operating Segments [Member] | Communication Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,752,423	4,819,535
Operating Segments [Member] | Defense and Advanced Technologies [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	367,759	341,450
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 10,967,687	$ 11,168,379