Retirement Plans (Projected Benefit Obligation) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted average assumptions used to determine the benefit obligation at year end
Discount rate	4.53%	3.93%	4.40%	4.54%
Rate of increase in compensation levels	3.50%	3.50%	3.50%
Weighted average assumptions used to determine net pension cost
Discount rate	3.93%	4.40%	4.54%
Rate of increase in compensation levels	3.50%	3.50%	3.50%
Expected long-term rate of return on plan assets	5.50%	5.50%	6.00%