Schedule II - Condensed Financial Information Of The Registrant (Condensed Balance Sheets) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Fixed maturity securities - available for sale, at market value	$ 5,201,921	$ 5,531,410
Equity securities, fair value	1,298,940	1,199,848
Other invested assets, at market value	385,776	420,744
Other invested assets, at fair value	1,515,052	1,068,711
Short-term investments	757,162	465,550
Cash	316,807	347,720
Total investments and cash	9,495,059	9,075,466
Accrued investment income	50,306	54,914
Income taxes recoverable	27,340	61,244
Other assets	247,505	236,955
TOTAL ASSETS	15,548,335	15,087,950
5.4% Senior notes due 10/15/2014	249,958	249,907
6.6% Long term notes due 05/01/2067	238,361	238,357
Junior subordinated debt securities payable		329,897
Accrued interest on debt and borrowings	4,781	4,781
Deferred tax liability	51,289	(214,175)
Other liabilities	272,468	290,724
Total liabilities	11,357,857	11,609,344
Common stock, par value: $0.01; 3,000 shares authorized; 1,000 shares issued and outstanding (2013 and 2012)
Additional paid-in capital	351,051	340,223
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of $47,195 at 2013 and $99,544 at 2012	87,648	184,867
Retained earnings	3,751,779	2,953,516
Total stockholder's equity	4,190,478	3,478,606	2,941,393
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY	15,548,335	15,087,950
Fixed maturities - available for sale, at amortized cost	5,116,600	5,289,619
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	1,000	1,000
Common stock, shares outstanding	1,000	1,000
Accumulated other comprehensive income (loss), deferred income tax expense (benefit)	47,195	99,544
Registrant [Member]
Condensed Financial Statements, Captions [Line Items]
Fixed maturity securities - available for sale, at market value	10,776	13,327
Equity securities, fair value	88,338	61,893
Other invested assets, at market value	3,046	12,943
Other invested assets, at fair value	1,515,052	1,068,711
Short-term investments	25,181	45,983
Cash	159	289
Total investments and cash	1,642,552	1,203,146
Investment in subsidiaries, at equity in the underlying net assets	3,136,782	3,068,916
Accrued investment income	97	165
Advances to affiliates	63,999	37,700
Income taxes recoverable	146,395	99,614
Other assets	17,487	25,908
TOTAL ASSETS	5,007,312	4,435,449
5.4% Senior notes due 10/15/2014	249,958	249,907
6.6% Long term notes due 05/01/2067	238,361	238,357
Junior subordinated debt securities payable		329,897
Accrued interest on debt and borrowings	4,781	4,781
Deferred tax liability	272,535	121,127
Due to subsidiaries	42,456	1,084
Other liabilities	8,743	11,690
Total liabilities	816,834	956,843
Common stock, par value: $0.01; 3,000 shares authorized; 1,000 shares issued and outstanding (2013 and 2012)
Additional paid-in capital	351,051	340,223
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of $47,195 at 2013 and $99,544 at 2012	87,648	184,867
Retained earnings	3,751,779	2,953,516
Total stockholder's equity	4,190,478	3,478,606
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY	5,007,312	4,435,449
Fixed maturities - available for sale, at amortized cost	10,778	13,051
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000,000	3,000,000
Common stock, shares issued	1,000,000	1,000,000
Common stock, shares outstanding	1,000,000	1,000,000
Accumulated other comprehensive income (loss), deferred income tax expense (benefit)	$ 47,195	$ 99,544
Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt instrument, interest rate, stated percentage	5.40%	5.40%
Debt instrument, maturity date	Oct. 15, 2014	Oct. 15, 2014
Senior Notes [Member] | Registrant [Member]
Condensed Financial Statements, Captions [Line Items]
Debt instrument, interest rate, stated percentage	5.40%
Debt instrument, maturity date	Oct. 15, 2014
Subordinated Debt [Member]
Condensed Financial Statements, Captions [Line Items]
Debt instrument, interest rate, stated percentage	6.60%	6.60%
Debt instrument, maturity date	May 01, 2067	May 01, 2067
Subordinated Debt [Member] | Registrant [Member]
Condensed Financial Statements, Captions [Line Items]
Debt instrument, interest rate, stated percentage		6.60%
Debt instrument, maturity date		May 01, 2067