Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Securities Available-for-Sale, Amortized Cost
Securities Available-for-Sale, Due in one year or less, Cost	$ 2,770
Securities Available-for-Sale, Due after one year through five years, Cost	15,041
Securities Available-for-Sale, Due after five years through ten years, Cost	81,726
Securities Available-for-Sale, Due after ten years, Cost	369,142
Securities Available-for-Sale, Cost, Total	468,679
Securities Available-for-Sale, Estimated Fair Value
Securities Available-for-Sale, Due in one year or less, Estimated Fair Value	2,788
Securities Available-for-Sale, Due after one year through five years, Estimated Fair Value	15,225
Securities Available-for-Sale, Due after five years through ten years, Estimated Fair Value	80,029
Securities Available-for-Sale, Due after ten years, Estimated Fair Value	365,969
Securities Available-for-Sale, Estimated Fair Value, Total	464,011
Securities Held-to-Maturity, Amortized Cost
Securities Held-to-Maturity, Due in one year or less, Cost	0
Securities Held-to-Maturity, Due after one year through five years, Cost	0
Securities Held-to-Maturity, Due after five years through ten years, Cost	0
Securities Held-to-Maturity, Due after ten years, Cost	72,308
Securities Held-to-Maturity, Amortized Cost	72,308	$ 75,169
Securities Held-to-Maturity, Estimated Fair Value
Securities Held-to-Maturity, Due in one year or less, Estimated Fair Value	0
Securities Held-to-Maturity, Due after one year through five years, Estimated Fair Value	0
Securities Held-to-Maturity, Due after five years through ten years, Estimated Fair Value	0
Securities Held-to-Maturity, Due after ten years, Estimated Fair Value	73,656
Securities Held-to-Maturity, Estimated Fair Value	$ 73,656	$ 76,445