Employee Benefits (Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Qualified Pension Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Expected Future Payments, Next Twelve Months	$ 3,964
Expected Future Payments, Year Two	2,931
Expected Future Payments, Year Three	3,387
Expected Future Payments, Year Four	3,784
Expected Future Payments, Year Five	4,378
Expected Future Payments, Thereafter	28,050
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Expected Future Payments, Next Twelve Months	897
Expected Future Payments, Year Two	891
Expected Future Payments, Year Three	879
Expected Future Payments, Year Four	868
Expected Future Payments, Year Five	891
Expected Future Payments, Thereafter	$ 4,221