Discontinued Operations (Summary Of Results Of Discontinued Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss from discontinued operations	$ (1,770)	$ (965)	$ (1,021)
Security And Certain Microphone And Receiver Operations [Member] | Discontinued Operations, Disposed of by Sale [Member]
Sales, net			207
Operating costs and expenses			(357)
Operating loss			(150)
Net loss from discontinued operations			(150)
Cardiac Diagnostic Monitoring Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Sales, net	1,161	1,212	1,209
Operating costs and expenses	(2,135)	(2,177)	(2,080)
Loss on impairment	(796)
Net loss from discontinued operations	$ (1,770)	$ (965)	$ (871)