Segment Reporting (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Mobile Connectivity [Member] | Mobile Comm Product Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	17.00%	18.00%	19.00%	21.00%
Mobile Connectivity [Member] | VSAT Airtime Service Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	41.00%	42.00%	41.00%	41.00%
Mobile Connectivity [Member] | Training and Content Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	16.00%	20.00%	18.00%	20.00%
Intertial Navigation [Member] | FOG System Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	18.00%	13.00%	16.00%	12.00%
Non-US [Member]
Segment Reporting Information [Line Items]
Percent of consolidated long-lived tangible assets	10.00%		10.00%		10.00%
Percent of Consolidated Net Sales	60.00%	60.00%	59.00%	61.00%