Retirement Plans (Schedule Of Net Periodic Benefit Costs) (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
UNITED STATES
Components of net periodic benefit cost:
Service cost	$ 0	$ 36	$ 38
Interest cost	684	746	742
Expected return on plan assets	(710)	(717)	(816)
Amortization of prior service cost	0	0	3
Recognized net actuarial loss	130	276	275
Net periodic pension cost	104	341	242
Foreign Plan
Components of net periodic benefit cost:
Interest cost	236	259	295
Expected return on plan assets	(280)	(290)	(324)
Amortization of prior service cost	19	17	27
Recognized net actuarial loss	192	275	225
Net periodic pension cost	$ 167	$ 261	$ 223