Retirement Plans (Schedule Of Net Benefit Costs) (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
United States
Components of net periodic benefit costs
Interest cost	$ 622	$ 684
Expected return on plan assets	(853)	(710)
Recognized net actuarial loss	96	130
Net periodic pension (income) cost	(135)	104
United Kingdom
Components of net periodic benefit costs
Interest cost	194	236
Expected return on plan assets	(260)	(280)
Amortization of prior service costs and transition amount	42	19
Recognized net actuarial loss	208	192
Net periodic pension (income) cost	$ 184	$ 167