Employee Benefits Plans (Details) - The assumptions used to determine the plan’s financial status and postretirement benefit cost	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Deferred Compensation Plan [Member]
Employee Benefits Plans (Details) - The assumptions used to determine the plan’s financial status and postretirement benefit cost [Line Items]
Discount rate for funded status	3.50%	3.55%
Discount rate for benefit cost	3.55%	3.50%
Supplemental Employee Retirement Plan [Member]
Employee Benefits Plans (Details) - The assumptions used to determine the plan’s financial status and postretirement benefit cost [Line Items]
Discount rate for funded status	3.55%	3.65%
Discount rate for benefit cost	3.65%	3.50%
Other Postretirement Benefit Plan [Member]
Employee Benefits Plans (Details) - The assumptions used to determine the plan’s financial status and postretirement benefit cost [Line Items]
Discount rate for funded status	3.20%	3.20%
Discount rate for benefit cost	3.20%	3.10%
Health care cost assumed trend rate for next year	6.00%	6.50%
Rate that the cost trend rate gradually declines to	5.50%	5.50%
Year that the rate reaches the rate it is assumed to remain at	2018	2018