Employee Benefit Plans (Schedule of Assumptions used to Determine Projected Benefit Obligation of the SERP) (Details) - Supplemental Executive Retirement Plan [Member]		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Weighted average discount rate		3.50%	4.00%	4.25%
Rate of increase in compensation levels	[1]

[1] 6.0% graded down to 3.25% over the first seven years of service