Segment Reporting Deprecation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Depreciation	$ 2,246	$ 1,760	$ 6,453	$ 5,016
Amortization expense	237	246	732	764
Operating Segments | Mobile connectivity
Segment Reporting Information [Line Items]
Depreciation	1,824	1,367	5,163	3,848
Amortization expense	237	246	732	764
Operating Segments | Inertial navigation
Segment Reporting Information [Line Items]
Depreciation	280	260	874	766
Amortization expense	0	0	0	0
Unallocated
Segment Reporting Information [Line Items]
Depreciation	142	133	416	402
Amortization expense	$ 0	$ 0	$ 0	$ 0