Segment Reporting Segment Reporting - Deprecation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Depreciation	$ 1,693	$ 1,907
Amortization expense	1,068	1,283
Mobile Connectivity [Member]
Segment Reporting Information [Line Items]
Depreciation	1,478	1,659
Amortization expense	1,068	1,283
Intertial Navigation [Member]
Segment Reporting Information [Line Items]
Depreciation	195	224
Amortization expense	0	0
Other Segments [Member]
Segment Reporting Information [Line Items]
Depreciation	20	24
Amortization expense	$ 0	$ 0