Employee Benefit Plans (Schedule of Employee Benefit Plans Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Noncurrent Liability	$ 34,426	$ 34,671
Pension Benefit Plan [Member]
Current Liability	398	393
Noncurrent Liability	26,542	20,118
Net Liability Recognized	26,940	20,511
Other Benefits Plan [Member]
Current Liability
Noncurrent Liability	7,884	14,553
Net Liability Recognized	$ 7,884	$ 14,553