Retirement Plans (Schedule Of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
United States
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 9	$ 0	$ 18
Interest cost	171	186	342	372
Expected return on plan assets	(178)	(179)	(355)	(358)
Recognized net actuarial loss	33	69	65	138
Net periodic pension cost	26	85	52	170
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Interest cost	55	75	110	150
Expected return on plan assets	(66)	(84)	(132)	(168)
Amortization of prior service costs and transition amount	4	5	8	10
Recognized net actuarial loss	71	39	142	78
Net periodic pension cost	$ 64	$ 35	$ 128	$ 70