Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS:
Fixed maturity investments available for sale, at fair value (amortized cost: 2011: $226,397; 2010: $828,544)	$ 244,016	$ 891,849
Fixed maturity investments trading, at fair value (amortized cost: 2011: $6,207,991; 2010: $5,714,322)	6,254,686	5,769,097
Equity securities trading, at fair value (cost: 2011: $356,370; 2010: $160,513)	367,483	174,976
Other invested assets trading, at fair value	540,409	347,632
Total investments	7,406,594	7,183,554
Cash and cash equivalents	633,996	756,995
Restricted cash	82,608	96,373
Insurance balances receivable	652,158	529,927
Prepaid reinsurance	226,721	187,287
Reinsurance recoverable	1,002,919	927,588
Accrued investment income	38,263	40,520
Net deferred acquisition costs	100,334	96,803
Goodwill	268,376	268,376
Intangible assets	53,898	56,876
Balances receivable on sale of investments	580,443	188,408
Net deferred tax assets	22,646	19,740
Other assets	53,202	75,184
Total assets	11,122,158	10,427,631
LIABILITIES:
Reserve for losses and loss expenses	5,225,143	4,879,188
Unearned premiums	1,078,412	962,203
Reinsurance balances payable	124,539	99,732
Balances due on purchases of investments	616,728	506,978
Dividends payable	14,302
Senior notes	797,949	797,700
Accounts payable and accrued liabilities	116,063	106,010
Total liabilities	7,973,136	7,351,811
SHAREHOLDERS' EQUITY:
Common shares, 2011: par value CHF 14.03 per share and 2010: par value CHF 15.00 per share, (2011: 40,003,642; 2010: 40,003,642 shares issued and 2011: 37,742,131; 2010: 38,089,226 shares outstanding)	557,153	600,055
Additional paid-in capital	78,225	170,239
Treasury shares, at cost (2011: 2,261,511; 2010: 1,914,416)	(136,590)	(112,811)
Retained earnings	2,635,750	2,361,202
Accumulated other comprehensive income: net unrealized gains on investments, net of tax	14,484	57,135
Total shareholders' equity	3,149,022	3,075,820
Total liabilities and shareholders' equity	$ 11,122,158	$ 10,427,631