Unaudited Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets
Fixed maturities, trading securities, at fair value (amortized cost: 2012, $12,994,604; 2011, $13,394,404)	$ 13,619,948	$ 13,941,829
Short-term investments, trading securities, at fair value (amortized cost: 2012, $31,943; 2011, $42,563)	31,984	42,571
Equities, trading securities, at fair value (cost: 2012, $1,005,118; 2011, $917,613)	1,050,017	944,691
Other invested assets	329,996	358,154
Total investments	15,031,945	15,287,245
Funds held - directly managed (cost: 2012, $1,197,479; 2011, $1,241,222)	1,233,008	1,268,010
Cash and cash equivalents, at fair value, which approximates amortized cost	1,512,418	1,342,257
Accrued investment income	160,392	189,074
Reinsurance balances receivable	2,358,432	2,059,976
Reinsurance recoverable on paid and unpaid losses	434,083	397,788
Funds held by reinsured companies	783,311	796,290
Deferred acquisition costs	620,277	547,202
Deposit assets	256,607	241,513
Net tax assets	37,711	66,574
Goodwill	455,533	455,533
Intangible assets	116,081	133,867
Other assets	72,165	70,044
Total assets	23,071,963	22,855,373
Liabilities
Unpaid losses and loss expenses	10,661,012	11,273,091
Policy benefits for life and annuity contracts	1,635,547	1,645,662
Unearned premiums	2,008,384	1,448,841
Other reinsurance balances payable	496,020	443,873
Deposit liabilities	256,773	249,382
Net tax liabilities	309,630	297,153
Accounts payable, accrued expenses and other	186,015	208,840
Debt related to senior notes	750,000	750,000
Debt related to capital efficient notes	70,989	70,989
Total liabilities	16,374,370	16,387,831
Shareholders' Equity
Common shares (par value $1.00, issued: 2012, 85,141,999 shares; 2011, 84,766,693 shares)	85,142	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	3,831,921	3,803,796
Accumulated other comprehensive income (loss):
Currency translation adjustment	2,317	4,267
Other accumulated comprehensive loss (net of tax of: 2012, $6,449; 2011, $6,590)	(16,967)	(16,911)
Retained earnings	4,460,655	4,035,103
Common shares held in treasury, at cost (2012, 22,584,510 shares; 2011, 19,444,365 shares)	(1,701,225)	(1,479,230)
Total shareholders' equity	6,697,593	6,467,542
Total liabilities and shareholders' equity	$ 23,071,963	$ 22,855,373