Investments (Summary Of Components Of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ 48,051	$ 188,124	$ 200,168	$ 333,821
Funds held interest income (expense)	2,021	1,422	10,237	7,390
Future policy benefit reserve income (expense)	(303)	(359)	(514)	(593)
Gross investment income	49,769	189,187	209,891	340,618
Investment expenses	(11,686)	(10,159)	(24,008)	(20,614)
Net investment income	38,083	179,028	185,883	320,004
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	133,918	126,593	271,842	253,301
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	3,662	4,596	7,183	8,103
Short-Term Investments and Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	1,687	5,393	3,862	9,598
Limited Partnerships [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	(88,254)	48,243	(66,686)	56,540
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ (2,962)	$ 3,299	$ (16,033)	$ 6,279