Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities
Net earnings	$ 196,294	$ 560,103
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Depreciation and amortization	65,199	45,146
Net realized capital (gains) losses	(50,902)	(67,989)
Other than temporary impairment losses	32,312	1,778
(Increase) decrease in reinsurance recoverables, net of reinsurance payable	50,668	10,378
(Increase) decrease in premium balances receivable	(87,487)	(32,711)
(Increase) decrease in ceded unearned premiums	(14,029)	4,862
(Increase) decrease in deferred acquisition costs	(17,960)	(46,540)
Increase (decrease) in unearned premiums	18,338	(1,375)
Increase (decrease) in loss and loss adjustment expenses	(188,267)	(452)
Change in unrealized foreign exchange (losses) gains	78,955	(24,878)
Gain on bargain purchase		(494,940)
Other, net	67,433	11,453
Net adjustments	(45,740)	(595,268)
Net cash provided by (used in) operating activities	150,554	(35,165)
Cash flows from investing activities
Purchases of debt securities	(1,903,342)	(443,860)
Purchases of equity securities	(1,376,991)	(113,044)
Sales of debt securities	2,178,552	192,637
Maturities and redemptions of debt securities	432,542	182,663
Sales of equity securities	863,175	465,542
Net (purchase) sale in short-term investments	(372,447)	625,330
Purchases of property and equipment	(1,557)	(1,127)
Purchase of subsidiary, net of cash acquired		(433,310)
Other, net	20,439	(4,195)
Net cash (used in) provided by investing activities	(159,629)	470,636
Cash flows from financing activities
Treasury stock acquisitions	(31,576)
Other, net	(8,735)	(1,126)
Net cash provided by (used in) financing activities	(40,311)	(1,126)
Effect of exchange rate changes on cash	(25,259)	1,122
Net (decrease) increase in cash	(74,645)	435,467
Cash at beginning of period	649,524	84,749
Cash at end of period	574,879	520,216
Cash paid during the period for:
Interest paid	8,438	8,438
Income taxes paid (refunds received)	$ (45,366)	$ 17,017