Retirement Plans - Schedule Of Net Benefit Costs (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
United States
Components of net periodic benefit costs
Interest cost	$ 224	$ 648	$ 622
Expected return on plan assets	(230)	(719)	(853)
Recognized net actuarial loss	53	125	96
Net periodic pension cost (income)	47	54	(135)
Settlement charge	0	2,210	0
Total pension expense (income)	47	2,264	(135)
Foreign Plan
Components of net periodic benefit costs
Interest cost			194
Expected return on plan assets			(260)
Amortization of prior service cost			42
Recognized net actuarial loss			208
Net periodic pension cost (income)			$ 184
United Kingdom
Components of net periodic benefit costs
Interest cost	184	221
Expected return on plan assets	(250)	(252)
Amortization of prior service cost	26	25
Recognized net actuarial loss	329	263
Net periodic pension cost (income)	$ 289	$ 257