Unaudited Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
CASH FLOWS PROVIDED BY OPERATING ACTIVITIES:
Net income	$ 328,835	$ 157,130
Adjustments to reconcile net income to cash provided by operating activities:
Net realized gains on sales of investments	(99,781)	(62,921)
Mark to market adjustments	(59,113)	95,698
Stock compensation expense	7,631	6,566
Undistributed income of equity method investments	13,744	(2,316)
Changes in:
Reserve for losses and loss expenses, net of reinsurance recoverables	101,911	12,901
Unearned premiums, net of prepaid reinsurance	258,006	305,776
Insurance balances receivable	(310,885)	(304,088)
Funds held	217,985	(51,231)
Reinsurance balances payable	51,159	69,620
Net deferred acquisition costs	(36,598)	(45,802)
Net deferred tax assets	1,934	(14,970)
Accounts payable and accrued liabilities	(53,397)	(45,601)
Other items, net	27,507	12,880
Net cash provided by operating activities	448,938	133,642
CASH FLOWS USED IN INVESTING ACTIVITIES:
Purchases of trading securities	(3,905,650)	(3,186,162)
Purchases of other invested assets	(181,419)	(141,805)
Sales of trading securities	3,705,229	3,171,977
Sales of other invested assets	184,166	126,491
Purchases of fixed assets	(5,601)	(3,363)
Change in restricted cash	21,638	(10,561)
Payments to Acquire Businesses, Net of Cash Acquired	(2,565)	0
Net cash used in investing activities	(184,202)	(43,423)
CASH FLOWS USED IN FINANCING ACTIVITIES:
Dividends paid - partial par value reduction	0	(12,981)
Dividends paid	(33,207)	0
Proceeds from the exercise of stock options	6,313	5,293
Share repurchases	(137,810)	(82,571)
Net cash used in financing activities	(164,704)	(90,259)
Effect of exchange rate changes on foreign currency cash	3,170	(7,736)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	103,202	(7,776)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	531,936	681,879
CASH AND CASH EQUIVALENTS, END OF PERIOD	635,138	674,103
Supplemental disclosure of cash flow information:
Cash paid for income taxes	18,061	12,671
Cash paid for interest expense	$ 27,000	$ 27,000