Condensed Financial Information of Registrant (Schedule Of Condensed Financial Information Of Registrant, Statements Of Cash Flow) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net cash used in operating activities	$ 148,062,000	$ 158,525,000	$ 91,781,000
Fixed maturity securities:
Calls or maturities	528,886,000	418,616,000	285,454,000
Equity securities:
Purchases	(590,562,000)	(379,963,000)	(432,869,000)
Sales	277,272,000	325,562,000	240,764,000
Calls	923,000	0	4,826,000
Net (increase) decrease in short-term investments	(58,949,000)	(93,737,000)	12,815,000
Other, net	2,255,000	12,026,000	6,868,000
Net cash (used in) provided by investing activities	(69,745,000)	124,615,000	33,100,000
Cash flows from financing activities:
Dividends paid to shareholders	(134,105,000)	(132,142,000)	(129,863,000)
Excess tax benefit from exercise of stock options	86,000	56,000	132,000
Payment to retire senior notes	0	(125,000,000)	0
Proceeds from stock options exercised	2,492,000	1,951,000	733,000
Net cash used in financing activities	(131,527,000)	(253,135,000)	(128,998,000)
Net (decrease) increase in cash	(53,210,000)	30,005,000	(4,117,000)
Cash:
Beginning of year	211,393,000	181,388,000	185,505,000
End of year	158,183,000	211,393,000	181,388,000
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	1,690,000	6,193,000	6,607,000
Income taxes paid (received)	18,481,000	8,503,000	18,792,000
Parent Company [Member]
Cash flows from operating activities:
Net cash used in operating activities	(5,590,000)	(312,000)	(4,441,000)
Cash flows from investing activities:
Dividends from subsidiaries	145,000,000	270,000,000	128,000,000
Fixed maturity securities:
Calls or maturities	0	0	265,000
Equity securities:
Purchases	(14,102,000)	(50,056,000)	(836,000)
Sales	7,308,000	43,520,000	2,070,000
Calls	0	0	895,000
Net (increase) decrease in short-term investments	(20,413,000)	(21,451,000)	(583,000)
Other, net	304,000	1,047,000	(110,000)
Net cash (used in) provided by investing activities	118,097,000	243,060,000	129,701,000
Cash flows from financing activities:
Dividends paid to shareholders	(134,105,000)	(132,142,000)	(129,863,000)
Excess tax benefit from exercise of stock options	86,000	56,000	132,000
Payment to retire senior notes	0	(125,000,000)	0
Proceeds from stock options exercised	2,492,000	1,951,000	733,000
Net cash used in financing activities	(131,527,000)	(255,135,000)	(128,998,000)
Net (decrease) increase in cash	(19,020,000)	(12,387,000)	(3,738,000)
Cash:
Beginning of year	29,219,000	41,606,000	45,344,000
End of year	10,199,000	29,219,000	41,606,000
SUPPLEMENTAL CASH FLOW DISCLOSURE
Interest paid	0	1,932,000	1,972,000
Income taxes paid (received)	$ 4,667,000	$ (1,252,000)	$ (8,755,000)