Investments in Other Equity Securities Investments in Other Equity Securities (Details) - USD ($)	3 Months Ended				12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Apr. 01, 2016	Dec. 31, 2016	Oct. 22, 2014	Sep. 02, 2014
Schedule of Cost-method Investments [Line Items]
Cost Method Investments Carrying Value	$ 3,900,000	$ 4,400,000			$ 4,400,000
Research and development	24,882,000			$ 23,563,000
Prepaid expenses and other current assets	27,368,000	26,319,000			26,319,000
Cost-method Investments, Other than Temporary Impairment	0			1,476,000
Vislink plc [Member]
Schedule of Cost-method Investments [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent							3.30%
Cost Method Investments Original Cost							$ 3,300,000
Cost Method Investments Carrying Value	300,000	$ 800,000			800,000
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	(200,000)				$ 300,000
Cost-method Investments, Other than Temporary Impairment			$ 1,200,000	$ 1,500,000
Stock Price Increase, Percentage		67.00%
Pebble Beach Systems [Member]
Schedule of Cost-method Investments [Line Items]
Cost Method Investments Carrying Value	300,000
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ (500,000)
Stock Price Decrease, Percentage	67.00%
Variable Interest Entity, Not Primary Beneficiary [Member] | EDC [Member]
Schedule of Cost-method Investments [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent						18.40%
Cost Method Investments Original Cost						$ 3,500,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 3,600,000
Cost-method Investments, Other than Temporary Impairment	$ 0