Segment Reporting (Details Textual)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mobile Connectivity [Member] | Mobile Comm Product Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	20.00%	23.00%	23.00%
Mobile Connectivity [Member] | VSAT Airtime Service Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	41.00%	37.00%	35.00%
Mobile Connectivity [Member] | Training and Content Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	20.00%	20.00%	21.00%
Intertial Navigation [Member] | FOG System Sales [Member]
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales	13.00%	10.00%	10.00%
Non-US [Member]
Segment Reporting Information [Line Items]
Percent of consolidated long-lived tangible assets (less than)	10.00%	10.00%
Percent of Consolidated Net Sales	62.00%	63.00%	67.00%
CANADA
Segment Reporting Information [Line Items]
Percent of Consolidated Net Sales		11.00%	10.00%