Unaudited Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
CASH FLOWS PROVIDED BY OPERATING ACTIVITIES:
Net income	$ 157,130	$ 314,507
Adjustments to reconcile net income to cash provided by operating activities:
Net realized gains on sales of investments	(62,921)	(46,834)
Mark to market adjustments	95,698	(94,732)
Stock compensation expense	6,566	9,294
Undistributed income of equity method investments	(2,316)	0
Changes in:
Reserve for losses and loss expenses, net of reinsurance recoverables	12,901	81,682
Unearned premiums, net of prepaid reinsurance	305,776	252,026
Insurance balances receivable	(304,088)	(187,038)
Funds held	(51,231)	(6,467)
Reinsurance balances payable	69,620	3,767
Net deferred acquisition costs	(45,802)	(29,484)
Net deferred tax assets	(14,970)	(3,458)
Accounts payable and accrued liabilities	(45,601)	(19,978)
Other items, net	12,880	28,488
Net cash provided by operating activities	133,642	301,773
CASH FLOWS (USED IN) PROVIDED BY INVESTING ACTIVITIES:
Purchases of trading securities	(3,186,162)	(4,005,352)
Purchases of other invested assets	(141,805)	(17,778)
Sales of available for sale securities	0	214,015
Sales of trading securities	3,171,977	3,959,204
Sales of other invested assets	126,491	108,759
Purchases of fixed assets	(3,363)	(879)
Change in restricted cash	(10,561)	(156,768)
Net cash (used in) provided by investing activities	(43,423)	101,201
CASH FLOWS USED IN FINANCING ACTIVITIES:
Partial par value reduction	(12,981)	(28,003)
Proceeds from the exercise of stock options	5,293	6,697
Share repurchases	(82,571)	(148,949)
Net cash used in financing activities	(90,259)	(170,255)
Effect of exchange rate changes on foreign currency cash	(7,736)	(2,265)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(7,776)	230,454
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	681,879	633,996
CASH AND CASH EQUIVALENTS, END OF PERIOD	674,103	864,450
Supplemental disclosure of cash flow information:
- Cash paid for income taxes	12,671	8,257
- Cash paid for interest expense	$ 27,000	$ 27,000