Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Amortized Cost
Due in one year or less	$ 32,645
Due after one year through five years	514,814
Due after five years through ten years	720,243
Due after ten years	337,004
Total	1,604,706	$ 1,673,864
Estimated Fair Value
Due in one year or less	2,108
Due after one year through five years	47,615
Due after five years through ten years	491,176
Due after ten years	915,360
Total	$ 1,456,259	$ 1,505,520