Employee Benefits Schedule of Weighted Average Actuarial Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Costs (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plan and SERP [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate used in calculating benefit obligation	3.96%	4.24%
Rate of increase in compensation used for calculating benefit obligation	3.50%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate used in calculating net periodic benefit cost	4.23%	3.94%	4.40%
Expected long-term return on plan assets used in calculating net periodic benefit cost	6.50%	6.75%	7.00%
Rate of increase in compensation used in calculating net periodic benefit cost	4.00%	4.00%	4.00%
Medical Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate used in calculating benefit obligation	4.10%	4.40%
Rate of increase in compensation used for calculating benefit obligation	3.50%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate used in calculating net periodic benefit cost	4.40%	4.00%	5.00%
Rate of increase in compensation used in calculating net periodic benefit cost	4.00%	4.00%	4.00%