Segment Reporting Segment Reporting - Deprecation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Depreciation	$ 2,568	$ 1,953
Amortization expense	959	1,097
Operating Segments | Mobile Connectivity
Segment Reporting Information [Line Items]
Depreciation	2,145	1,470
Amortization expense	959	1,097
Operating Segments | Intertial Navigation
Segment Reporting Information [Line Items]
Depreciation	286	218
Amortization expense	0	0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Depreciation	137	265
Amortization expense	$ 0	$ 0