Revisions To Financial Statements (Schedule Of Prior Period Financial Statements - Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 190,880	$ 332,868	$ 207,492	$ 687,419
Decrease (increase) in premiums receivable			(252,609)	(174,583)
Decrease (increase) in funds held by reinsureds, net			(23,498)	(55,421)
Decrease (increase) in income taxes			$ (25,000)	180,126
As Previously Reported [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)		342,855		691,755
Decrease (increase) in premiums receivable				(178,319)
Decrease (increase) in funds held by reinsureds, net				(56,180)
Decrease (increase) in income taxes				180,285
Impact of Revisions [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)		$ (9,987)		(4,336)
Decrease (increase) in premiums receivable				3,736
Decrease (increase) in funds held by reinsureds, net				759
Decrease (increase) in income taxes				$ (159)