Investments (Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity) (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Investments [Abstract]
Securities Available-for-Sale, Due in one year or less, Cost	$ 2,965,000
Securities Available-for-Sale, Due after one year through five years, Cost	85,102,000
Securities Available-for-Sale, Due after five years through ten years, Cost	434,093,000
Securities Available-for-Sale, Due after ten years, Cost	957,385,000
Securities Available-for-Sale, Cost, Total	1,479,545,000	$ 1,673,864,000
Securities Available-for-Sale, Due in one year or less, Estimated Fair Value	2,923,000
Securities Available-for-Sale, Due after one year through five years, Estimated Fair Value	81,176,000
Securities Available-for-Sale, Due after five years through ten years, Estimated Fair Value	404,955,000
Securities Available-for-Sale, Due after ten years, Estimated Fair Value	849,083,000
Debt Securities, Available-for-sale, Total	$ 1,338,137,000	$ 1,505,520,000