Accumulated Other Comprehensive Income (Summary Of Accumulated Other Comprehensive Income) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 20,991
Net current period other comprehensive (loss)	(750)
Balance	20,241
Foreign Currency Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	23,575
Net current period other comprehensive (loss)	(800)
Balance	22,775
Unrealized Gain (Losses) On Available-For-Sale Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	8
Net current period other comprehensive (loss)	(2)
Balance	6
Accrued Pension Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(2,592)
Net current period other comprehensive (loss)	52
Balance	$ (2,540)