Investments (Estimated Fair Value Of Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fixed maturity securities:
Due in one year or less	$ 166,423
Due after one year through five years	377,334
Due after five years through ten years	208,815
Due after ten years	2,232,589
Total	$ 2,985,161	$ 2,892,777
External credit rating, non investment grade [Member]
Credit Derivatives [Line Items]
Percentage of fixed maturities	3.00%