OPERATING SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
REVENUE
Segment totals before income taxes	$ 144,151	$ 137,280
Net investment income	12,886	15,293
Net realized gains	3,684	11,416
Consolidated revenue	160,721	163,989
NET EARNINGS
Net underwriting income	19,798	14,941
Net investment income	12,886	15,293
Net realized gains	3,684	11,416
General corporate expense and interest on debt	(3,898)	(3,487)
Equity in earnings of unconsolidated investee	3,499	2,946
Earnings before income taxes	35,969	41,109
Income tax expense	11,122	13,071
Net earnings	24,847	28,038
Casualty
REVENUE
Segment totals before income taxes	72,969	63,510
NET EARNINGS
Net underwriting income	4,104	552
Property
REVENUE
Segment totals before income taxes	44,981	46,992
NET EARNINGS
Net underwriting income	10,924	11,917
Surety
REVENUE
Segment totals before income taxes	26,201	26,778
NET EARNINGS
Net underwriting income	$ 4,770	$ 2,472