Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less	$ 3,116
Due after one year through five years	45,143
Due after five years through ten years	396,831
Due after ten years	1,018,687
Total	1,463,777	$ 1,384,607
Estimated Fair Value
Due in one year or less	3,146
Due after one year through five years	45,506
Due after five years through ten years	391,126
Due after ten years	969,735
Total	$ 1,409,513	$ 1,408,165