Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Components of Net Periodic Benefit Cost
Service cost	$ 995	$ 1,173
Interest cost	1,155	1,082
Net loss	213	427
Net periodic pension cost	$ 2,363	$ 2,682
Weighted Average Assumptions for Expense
Discount Rate	4.50%	4.75%
Rate of Compensation Increase	4.40%	4.40%