OPERATING SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
REVENUES
Segment totals before income taxes	$ 163,702	$ 149,943	$ 462,406	$ 428,807
Net investment income	13,598	14,221	39,331	44,340
Net realized gains	10,999	5,481	18,425	16,233
Consolidated revenue	188,299	169,645	520,162	489,380
NET EARNINGS
Net underwriting income	31,818	18,530	77,175	55,094
Net investment income	13,598	14,221	39,331	44,340
Net realized gains	10,999	5,481	18,425	16,233
General corporate expense and interest on debt	(3,670)	(3,611)	(10,773)	(10,438)
Equity in earnings of unconsolidated investee	2,564	1,859	10,696	8,928
Earnings before income taxes	55,309	36,480	134,854	114,157
Income tax expense	17,662	11,017	42,458	35,908
Net earnings	37,647	25,463	92,396	78,249
Casualty
REVENUES
Segment totals before income taxes	83,966	68,194	235,307	197,409
NET EARNINGS
Net underwriting income	20,799	10,806	39,517	22,409
Property
REVENUES
Segment totals before income taxes	52,705	54,741	147,305	151,581
NET EARNINGS
Net underwriting income	6,468	(310)	19,614	11,317
Surety
REVENUES
Segment totals before income taxes	27,031	27,008	79,794	79,817
NET EARNINGS
Net underwriting income	$ 4,551	$ 8,034	$ 18,044	$ 21,368