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