Income Taxes - Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Deferred tax assets:
Net operating loss carryforwards	$ 184,177	$ 202,752
Tax credit carryforwards	189,970	145,369
Other	46,376	74,962
Valuation allowance	(29,049)	(17,728)
Total deferred tax assets	391,474	405,355
Deferred tax liabilities:
Intangible assets	(73,403)	(98,099)
Property, equipment and satellites	(96,661)	(174,428)
Total deferred tax liabilities	(170,064)	(272,527)
Net deferred tax assets	$ 221,410	$ 132,828