Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Components of Net Periodic Benefit Cost
Service Cost	$ 1,254	$ 998
Interest Cost	1,306	1,393
Net Loss	(540)	(210)
Net Periodic Pension Cost	$ 3,100	$ 2,601
Weighted Average Assumptions for Expense
Discount Rate	2.80%	3.40%
Rate of Compensation Increase	4.40%	4.40%