Segment Information - Segment Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Apr. 01, 2019	Mar. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,883,868	$ 4,242,149	$ 3,915,287
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	758,758		677,529
Operating Segments [Member] | Satellite Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	86,252		85,907
Operating Segments [Member] | Commercial Networks [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	188,269		183,200
Operating Segments [Member] | Government Systems [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	484,237		408,422
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,125,110		$ 3,237,758