Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized Cost
Due in one year or less	$ 2,630
Due after one year through five years	108,133
Due after five years through ten years	406,455
Due after ten years	986,354
Total	1,503,572	$ 1,479,545
Estimated Fair Value
Due in one year or less	2,598
Due after one year through five years	102,535
Due after five years through ten years	375,247
Due after ten years	867,277
Total	$ 1,347,657	$ 1,338,137