International Retirement Plan (Components Of Net Periodic Benefit Costs And Other Amounts Recognized In Other Comprehensive Income) (Details) - International Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 184	$ 154
Interest cost	131	159
Amortization of actuarial loss	244	128
Total	559	441
Net (gain) loss	(555)	1,437
Total expense recognized in net periodic benefit cost and other comprehensive income	$ 4	$ 1,878