Retirement Plans (Schedule Of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 36	$ 38	$ 23
Interest cost	746	742	771
Expected return on plan assets	(717)	(816)	(968)
Amortization of prior service cost and transition amount		3	1
Recognized net actuarial loss	(276)	(275)	(65)
Net periodic pension cost	$ 341	$ 242	$ (108)
Net periodic benefit costs: Discount rate	4.30%	4.30%	4.00%
Net periodic benefit costs: Expected return on plan assets	5.20%	5.20%	5.50%
Projected benefit obligation	$ 18,241	$ 17,759	$ 18,925
Accumulated benefit obligation	18,241	17,759
Fair value of plan assets	14,180	14,235	15,205
UNITED KINGDOM
Defined Benefit Plan Disclosure [Line Items]
Interest cost	259	295	360
Expected return on plan assets	(290)	(324)	(370)
Amortization of transition amount	0		(50)
Amortization of prior service cost and transition amount	17	27	30
Recognized net actuarial loss	(275)	(225)	(185)
Net periodic pension cost	$ 261	$ 223	$ 155
Projected benefit obligation: Discount rate	2.70%	4.00%	3.60%
Net periodic benefit costs: Expected return on plan assets	4.40%	5.20%	5.00%
Projected benefit obligation	$ 8,104	$ 7,862	$ 8,797
Accumulated benefit obligation	8,104	7,862
Fair value of plan assets	$ 5,826	$ 6,661	$ 6,757