Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments:
Fixed maturity securities	$ 11,892,412	$ 11,312,037
Equity securities available for sale	425,322	443,439
Arbitrage trading account	417,446	397,312
Investment funds	747,638	680,638
Loans receivable	371,408	263,187
Real estate	433,686	342,905
Total investments	14,287,912	13,439,518
Cash and cash equivalents	1,189,564	911,742
Premiums and fees receivable	1,409,246	1,206,204
Due from reinsurers	1,309,463	1,215,679
Accrued investment income	131,790	133,776
Prepaid reinsurance premiums	311,355	258,271
Deferred policy acquisition costs	400,727	364,937
Real estate, furniture and equipment	258,368	262,275
Goodwill	87,865	87,865
Trading account receivables from brokers and clearing organizations	387,352	318,240
Current federal and foreign income taxes	5,122	9,670
Other assets	154,148	195,696
Total assets	19,932,912	18,403,873
Liabilities:
Reserves for losses and loss expenses	9,562,877	9,337,134
Unearned premiums	2,480,449	2,189,575
Due to reinsurers	303,424	241,204
Trading account securities sold but not yet purchased	149,405	62,514
Deferred federal and foreign income taxes	69,968	2,835
Other liabilities	912,357	866,229
Junior subordinated debentures	243,154	242,997
Senior notes and other debt	1,877,431	1,500,503
Total liabilities	15,599,065	14,442,991
Equity:
Preferred stock, par value $.10 per share: Authorized 5,000,000 shares; issued and outstanding - none	0	0
Common stock, par value $.20 per share:Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 135,956,622 and 137,520,019 shares	47,024	47,024
Additional paid-in capital	936,915	941,109
Retained earnings	4,800,537	4,491,162
Accumulated other comprehensive income	508,152	354,851
Treasury stock, at cost, 99,161,296 and 97,597,899 shares	(1,968,227)	(1,880,790)
Total stockholders' equity	4,324,401	3,953,356
Noncontrolling interests	9,446	7,526
Total equity	4,333,847	3,960,882
Total liabilities and equity	$ 19,932,912	$ 18,403,873