Net Periodic Pension Cost (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Retirement Plans
Interest cost	$ 89	$ 113
Amortization of net loss	35	36
Expected return on plan assets	(171)	(149)
Net periodic pension cost	(47)
Contributed amount