Segment Information - Segment Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Mar. 31, 2022
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 6,510,280	$ 6,389,346
Assets of discontinued operations	285,249	275,102
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	937,221	914,558
Operating Segments [Member] | Satellite Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	411,774	444,976
Operating Segments [Member] | Commercial Networks [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	259,646	202,941
Operating Segments [Member] | Government Systems [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	265,801	266,641
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 5,287,810	$ 5,199,686