Derivative Instruments (Effect Of Fair Value Hedges On Consolidated Statements Of Income) (Details) - Not Designated As Hedging Instruments [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ (1,785)	$ (145)
Other Non-Interest Income [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	(1)	6
Mortgage Banking Income [Member] | Mortgage Derivatives [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ (1,784)	$ (151)