Satellite Network and Other Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property Plant And Equipment [Line Items]
Depreciation and amortization expense	$ 12,678	$ 12,223
Products and Services and Internal-use Software [Member]
Property Plant And Equipment [Line Items]
Company capitalized internal costs attributable to design, development and enhancements of Company's products and services and internal-use software	3,485	3,807
Fixed Assets [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization expense	9,443	8,942
Fixed Assets [Member] | Service [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization expense related to cost of services and cost of product sales	4,250	4,287
Fixed Assets [Member] | Product [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization expense related to cost of services and cost of product sales	693	1,028
Internal-use Software [Member]
Property Plant And Equipment [Line Items]
Amortization of internal-use software	$ 863	$ 936