Unaudited Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Assets
Fixed maturities, trading securities, at fair value (amortized cost: 2012, $13,555,701; 2011, $13,394,404)	$ 14,338,499	$ 13,941,829
Short-term investments, trading securities, at fair value (amortized cost: 2012, $161,083; 2011, $42,563)	161,137	42,571
Equities, trading securities, at fair value (cost: 2012, $975,023; 2011, $917,613)	1,071,528	944,691
Other invested assets	341,555	358,154
Total investments	15,912,719	15,287,245
Funds held - directly managed (cost: 2012, $1,142,593; 2011, $1,241,222)	1,188,186	1,268,010
Cash and cash equivalents, at fair value, which approximates amortized cost	1,336,362	1,342,257
Accrued investment income	175,066	189,074
Reinsurance balances receivable	2,329,907	2,059,976
Reinsurance recoverable on paid and unpaid losses	369,960	397,788
Funds held by reinsured companies	805,178	796,290
Deferred acquisition costs	602,660	547,202
Deposit assets	256,587	241,513
Net tax assets	34,547	66,574
Goodwill	455,533	455,533
Intangible assets	107,188	133,867
Other assets	66,237	70,044
Total assets	23,640,130	22,855,373
Liabilities
Unpaid losses and loss expenses	10,761,302	11,273,091
Policy benefits for life and annuity contracts	1,703,147	1,645,662
Unearned premiums	1,810,881	1,448,841
Other reinsurance balances payable	504,820	443,873
Deposit liabilities	255,986	249,382
Net tax liabilities	356,851	297,153
Accounts payable, accrued expenses and other	347,152	208,840
Debt related to senior notes	750,000	750,000
Debt related to capital efficient notes	70,989	70,989
Total liabilities	16,561,128	16,387,831
Shareholders' Equity
Common shares (par value $1.00, issued: 2012, 85,204,067 shares; 2011, 84,766,693 shares)	85,204	84,767
Preferred shares (par value $1.00; issued and outstanding: 2012 and 2011, 35,750,000 shares; aggregate liquidation value: 2012 and 2011, $893,750)	35,750	35,750
Additional paid-in capital	3,840,641	3,803,796
Accumulated other comprehensive income (loss):
Currency translation adjustment	35,309	4,267
Other accumulated comprehensive loss (net of tax of: 2012, $6,605; 2011, $6,590)	(17,794)	(16,911)
Retained earnings	4,893,729	4,035,103
Common shares held in treasury, at cost (2012, 23,837,410 shares; 2011, 19,444,365 shares)	(1,793,837)	(1,479,230)
Total shareholders' equity	7,079,002	6,467,542
Total liabilities and shareholders' equity	$ 23,640,130	$ 22,855,373