Satellite Network and Other Equipment - Summary of Satellite Network and Other Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	$ 292,944	$ 286,434
Less: accumulated depreciation and amortization	(78,885)	(70,593)
Satellite network and other equipment, net	214,059	215,841
Land [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	381	381
Satellite Network [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	232,228	231,782
Capitalized Software [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	36,056	30,758
Computer Hardware [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	4,767	4,707
Other [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	7,624	7,522
Assets under Construction [Member]
Property Plant And Equipment [Line Items]
Satellite network and other equipment, gross	$ 11,888	$ 11,284