Reserves For Losses, LAE And Future Policy Benefit Reserve (Summary Of Activity In The Reserve For Losses And LAE) (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Reserves For Losses, LAE And Future Policy Benefit Reserve [Abstract]
Gross reserves beginning of period	$ 13,121,177	$ 11,578,096	$ 11,578,096
Less reinsurance recoverables on unpaid losses	(3,650,716)	(3,951,474)	(3,951,474)
Net reserves beginning of period	9,470,461	7,626,622	7,626,622
Incurred related to: Current year	2,520,596	2,450,567
Incurred related to : Prior years	9,031	(865)
Total incurred losses and LAE	2,529,627	2,449,702
Paid related to: Current year	775,023	550,907
Paid related to: Prior years	1,063,144	903,025
Total paid losses and LAE	1,838,167	1,453,932
Foreign exchange/translation adjustment	(16,668)	9,986
Net reserves end of period	10,145,252	8,632,376	9,470,461
Plus reinsurance recoverables on unpaid losses	3,593,105	3,772,228	3,650,716
Gross reserves end of period	$ 13,738,357	$ 12,404,604	$ 13,121,177