Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Securities Available-for-Sale, Amortized Cost
Securities Available-for-Sale, Due in one year or less, Cost	$ 1,373
Securities Available-for-Sale, Due after one year through five years, Cost	17,051
Securities Available-for-Sale, Due after five years through ten years, Cost	183,757
Securities Available-for-Sale, Due after ten years, Cost	575,932
Securities Available-for-Sale, Cost, Total	778,113
Securities Available-for-Sale, Estimated Fair Value
Securities Available-for-Sale, Due in one year or less, Estimated Fair Value	1,375
Securities Available-for-Sale, Due after one year through five years, Estimated Fair Value	17,402
Securities Available-for-Sale, Due after five years through ten years, Estimated Fair Value	188,514
Securities Available-for-Sale, Due after ten years, Estimated Fair Value	585,212
Securities Available-for-Sale, Estimated Fair Value, Total	792,503
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	4,932
Securities Held-to-Maturity, Due after ten years, Cost	48,430
Securities Held-to-Maturity, Amortized Cost	53,362	$ 60,827
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	5,434
Securities Held-to-Maturity, Due after ten years, Estimated Fair Value	49,243
Securities Held-to-Maturity, Estimated Fair Value	$ 54,677	$ 60,706