Consolidated Balance Sheet Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets [Abstract]
Fixed maturity securities	$ 11,986,477	$ 11,616,844
Equity securities	322,773	283,338
Arbitrage trading account	681,077	522,128
Investment funds	956,701	1,067,495
Loans receivable	373,166	343,583
Real estate	752,376	715,242
Total investments	15,072,570	14,548,630
Cash and cash equivalents	643,575	839,738
Premiums and fees receivable	1,651,407	1,557,480
Due from reinsurers	1,508,311	1,533,103
Accrued investment income	130,510	118,329
Prepaid reinsurance premiums	404,275	367,803
Deferred policy acquisition costs	475,244	452,101
Property, furniture and equipment	337,982	339,448
Federal and foreign income taxes	0	44,857
Goodwill	110,242	110,146
Trading account receivables from brokers and clearing organizations	74,786	304,936
Other assets	295,365	335,225
Total assets	20,704,267	20,551,796
Liabilities:
Reserves for losses and loss expenses	10,214,994	10,080,941
Unearned premiums	2,979,086	2,781,437
Due to reinsurers	236,688	276,755
Trading account securities sold but not yet purchased	91,118	162,278
Federal and foreign income taxes	59,184	0
Other liabilities	679,784	848,749
Junior subordinated debentures	339,865	339,800
Senior notes and other debt	1,692,690	1,692,442
Total liabilities	16,293,409	16,182,402
Equity:
Authorized 5,000,000 shares; issued and outstanding - none	0	0
Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 127,580,268 and 132,233,167 shares, respectively	47,024	47,024
Additional paid-in capital	970,305	967,440
Retained earnings	5,421,913	5,265,015
Accumulated other comprehensive income	258,883	189,391
Treasury stock, at cost, 107,537,650 and 102,884,751 shares, respectively	2,322,181	2,132,835
Total stockholders’ equity	4,375,944	4,336,035
Noncontrolling interests	34,914	33,359
Total equity	4,410,858	4,369,394
Total liabilities and equity	$ 20,704,267	$ 20,551,796