Derivative Instruments (Effect Of Fair Value Hedges On Consolidated Statements Of Income) (Details) - Not Designated As Hedging Instruments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ (2,639)	$ 1,983	$ 1,143
Interest rate contracts | Other Non- Interest Income
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	20	76	44
Mortgage derivatives | Mortgage Banking Income
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ (2,659)	$ 1,907	$ 1,099