Securities Available For Sale (Summary Of Maturities Distribution Of The Amortized Cost And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Securities Available For Sale [Abstract]
Amortized Cost, Due one year or less	$ 134
Amortized Cost, Due after one year through five years	6,230
Amortized Cost, Due after five years through ten years	17,482
Amortized Cost, Due after ten years	508,279
Securities Available for Sale, Amortized Cost	532,125	$ 496,179
Estimated Fair Value, Due one year or less	134
Estimated Fair Value, Due after one year through five years	6,283
Estimated Fair Value, Due after five years through ten years	17,722
Estimated Fair Value, Due after ten years	504,717
Securities Available for Sale, Estimated Fair Value	$ 528,856	$ 504,969