Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2016	May 31, 2013	Sep. 30, 2016	Mar. 31, 2016
Unfavorable Regulatory Action [Member]
Long-term Purchase Commitment [Line Items]
U.S. government contract-related reserves			$ 1.7	$ 2.5
Satellite - ViaSat-2 [Member] | Capital Addition [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount		$ 358.0
ViaSat-3 Class Satellites [Member] | Capital Addition [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount	$ 368.3