Condensed Financial Information of Registrant (Schedule Of Condensed Financial Information Of Registrant, Statements Of Cash Flow) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net cash provided by (used in) operating activities	$ 190,244	$ 246,535	$ 209,804
Equity securities available for sale in nature
Purchases	(965,701)	(542,494)	(831,796)
Sales	805,417	745,058	872,997
(Decrease) in payable for securities, net	(1,387)	9,294	1,702
Business acquisition, net of cash acquired	7,771	0	0
Other, net	2,473	3,472	1,741
Net cash used in investing activities	(81,682)	(194,035)	(18,351)
Cash flows from financing activities:
Dividends paid to shareholders	(136,386)	(135,496)	(134,776)
Excess tax benefit from exercise of stock options	27	148	202
Proceeds from stock options exercised	2,111	6,247	1,446
Proceeds from bank loan	0	100,000	50,000
Net cash used in financing activities	(134,248)	(29,101)	(83,128)
Net increase (decrease) in cash	(25,686)	23,399	108,325
Cash:
Beginning of year	289,907	266,508	158,183
End of year	264,221	289,907	266,508
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	2,989	2,543	998
Income taxes paid (received)	31,390	61,139	16,503
Parent Company [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities	548	(3,434)	(843)
Cash flows from investing activities:
Capital contribution to subsidiaries	(90,125)	(30,125)	(40,125)
Distributions received from special purpose entities	8,883	6,756	0
Dividends received from subsidiaries	133,000	225,000	120,000
Purchases of fixed maturity securities available for sale in nature	(571)	0	0
Equity securities available for sale in nature
Purchases	(146,236)	(254,572)	(25,038)
Sales	192,005	90,422	25,798
(Decrease) in payable for securities, net	0	(2,489)	2,489
Net decrease in short-term investments	(8,612)	(1,346)	(36,085)
Business acquisition, net of cash acquired	(6,000)	0	0
Other, net	1,945	2,191	895
Net cash used in investing activities	101,513	38,529	120,104
Cash flows from financing activities:
Dividends paid to shareholders	(136,386)	(135,496)	(134,776)
Excess tax benefit from exercise of stock options	27	148	202
Proceeds from stock options exercised	2,111	6,247	1,446
Proceeds from bank loan	0	100,000	50,000
Net cash used in financing activities	(134,248)	(29,101)	(83,128)
Net increase (decrease) in cash	(32,187)	5,994	36,133
Cash:
Beginning of year	52,326	46,332	10,199
End of year	20,139	52,326	46,332
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	2,153	1,757	318
Income taxes paid (received)	$ 1,807	$ 2,112	$ (827)