Retirement Plans (Schedule Of Net Benefit Costs) (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
United States
Defined Benefit Plan Disclosure
Interest cost	$ 162	$ 155	$ 324	$ 311
Expected return on plan assets	(180)	(213)	(360)	(427)
Recognized net actuarial loss	31	24	63	48
Net periodic pension cost	13	(34)	27	(68)
United Kingdom
Defined Benefit Plan Disclosure
Interest cost	54	52	108	104
Expected return on plan assets	(61)	(71)	(122)	(142)
Amortization of prior service costs and transition amount	11	5	22	10
Recognized net actuarial loss	53	49	106	98
Net periodic pension cost	$ 57	$ 35	$ 114	$ 70