Income Taxes - Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 202,752	$ 222,332
Tax credit carryforwards	145,369	129,333
Other	74,962	64,459
Valuation allowance	(17,728)	(17,089)
Total deferred tax assets	405,355	399,035
Deferred tax liabilities:
Intangible assets	(98,099)	(82,295)
Property, equipment and satellites	(174,428)	(182,030)
Total deferred tax liabilities	(272,527)	(264,325)
Net deferred tax assets	$ 132,828	$ 134,710