Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities
Net earnings	$ 292,187	$ 283,139
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in premium, claims and other receivables	(52,395)	6,623
Change in reinsurance recoverables	(138,103)	47,149
Change in ceded unearned premium	(44,809)	(39,918)
Change in loss and loss adjustment expense payable	241,126	16,052
Change in unearned premium	95,395	87,177
Change in reinsurance, premium and claims payable, excluding restricted cash	21,516	(32,743)
Change in accounts payable and accrued liabilities	(145,740)	79,500
Stock-based compensation expense	10,100	10,361
Depreciation and amortization expense	13,962	13,919
Gain on investments	(31,115)	(7,491)
Other, net	9,288	32,267
Cash provided by operating activities	271,412	496,035
Investing activities
Sales of available for sale fixed maturity securities	337,895	293,969
Sales of equity securities	95,989	7,145
Sales of other investments	23,719	6,974
Maturity or call of available for sale fixed maturity securities	488,817	504,583
Maturity or call of held to maturity fixed maturity securities	0	28,511
Cost of available for sale fixed maturity securities acquired	(1,109,233)	(1,056,909)
Cost of equity securities acquired	(226,601)	(205,092)
Change in short-term investments	134,515	(5,401)
Payments for purchase of businesses, net of cash received	(8,214)	(32,590)
Other, net	(5,248)	(9,885)
Cash used by investing activities	(268,361)	(468,695)
Financing activities
Advances on line of credit	130,000	140,000
Payments on line of credit	(60,000)	(70,000)
Sale of common stock	8,725	40,105
Purchase of common stock	(47,869)	(135,151)
Dividends paid	(49,773)	(47,617)
Other, net	(487)	5,066
Cash used by financing activities	(19,404)	(67,597)
Net decrease in cash	(16,353)	(40,257)
Cash at beginning of year	71,390	104,550
Cash at end of period	$ 55,037	$ 64,293