Employee Benefit Plans (Schedule of Amounts in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax	$ 17,883	$ 14,335
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Prior Service Cost (Credit), after Tax	7	13
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax, Total	17,890	14,348
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax	860	729
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Prior Service Cost (Credit), after Tax	(8)	(8)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax, Total	$ 852	$ 721