Statutory Balances and Accounting Practices (Schedule Of Statutory Net Income And Capital And Surplus) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statutory Balances And Accounting Practices [Abstract]
Statutory net income	[1]	$ 82,359	$ 123,984	$ 155,654
Statutory capital and surplus		$ 1,441,571	$ 1,451,950	$ 1,438,281
RBC authorized control level		375.00%	375.00%	375.00%
Minimum RBC authorized control level		200.00%	200.00%	200.00%

[1] Statutory net income reflects differences from GAAP net income, including changes in the fair value of the investment portfolio as a result of the application of the fair value option.