Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Components of Net Periodic Benefit Cost
Service cost	$ 1,200	$ 1,001
Interest cost	1,242	1,228
Net loss	532	291
Net periodic pension cost	$ 2,974	$ 2,520
Weighted Average Assumptions for Expense
Discount Rate	4.50%	3.80%
Rate of Compensation Increase	4.40%	4.40%