Reserves For Losses And LAE (Summary Of Incurred Losses With Respect To A&E Reserves On Both Gross And Net Of Reinsurance Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserves For Losses And LAE [Abstract]
Gross basis: Beginning of period reserves	$ 257,921	$ 347,495	$ 448,993
Gross basis: Incurred losses	1,540	2,071	(2,473)
Gross basis: Paid losses	(40,120)	(91,645)	(99,026)
Gross basis: End of period reserves	219,341	257,921	347,495
Net basis: Beginning of period reserves	196,574	223,548	269,153
Net basis: Incurred losses	(4,753)
Net basis: Paid losses	(24,382)	(26,974)	(45,605)
Net basis: End of period reserves	$ 167,439	$ 196,574	$ 223,548