Accumulated Other Comprehensive Income (Summary Of Accumulated Other Comprehensive Income) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 20,991
Net current-period other comprehensive (loss)	(8,659)
Balance	12,332
Foreign Currency Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	23,575
Net current-period other comprehensive (loss)	(8,761)
Balance	14,814
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)	104
Balance	$ (2,488)