Segment Reporting Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Depreciation	$ 7,608	$ 7,193	$ 6,127
Amortization expense	4,956	5,526	3,859
Other Segments [Member]
Segment Reporting Information [Line Items]
Depreciation	461	389	365
Amortization expense	0	0	0
Mobile Connectivity [Member]
Segment Reporting Information [Line Items]
Depreciation	6,084	5,843	4,827
Amortization expense	4,956	5,526	3,859
Intertial Navigation [Member]
Segment Reporting Information [Line Items]
Depreciation	1,063	961	935
Amortization expense	$ 0	$ 0	$ 0