OPERATING SEGMENT INFORMATION (Details 2) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenue by major product
Net premiums earned	$ 146,552,000	$ 128,334,000	$ 393,429,000	$ 366,356,000
Casualty
Revenue by major product
Net premiums earned	60,626,000	57,684,000	173,937,000	175,690,000
Increase (decrease) in segment revenue due to reclassification of business division			500,000
Decrease in net earnings due to reclassification of business division			1,000,000
Casualty | General Liability
Revenue by major product
Net premiums earned	20,693,000	23,874,000	63,817,000	73,653,000
Casualty | Commercial and personal umbrella
Revenue by major product
Net premiums earned	15,825,000	15,361,000	47,110,000	45,855,000
Casualty | Commercial transportation
Revenue by major product
Net premiums earned	8,326,000	10,088,000	25,843,000	30,871,000
Casualty | Executive products
Revenue by major product
Net premiums earned	4,455,000	4,015,000	13,013,000	11,752,000
Casualty | Specialty programs
Revenue by major product
Net premiums earned	948,000	1,604,000	3,377,000	5,717,000
Casualty | P&C package business
Revenue by major product
Net premiums earned	6,126,000		10,235,000
Casualty | Professional services
Revenue by major product
Net premiums earned	2,916,000	1,092,000	6,304,000	2,676,000
Casualty | Other
Revenue by major product
Net premiums earned	1,337,000	1,650,000	4,238,000	5,166,000
Property
Revenue by major product
Net premiums earned	59,226,000	50,167,000	148,015,000	132,133,000
Property | Commercial property
Revenue by major product
Net premiums earned	20,295,000	20,122,000	60,894,000	60,284,000
Property | Marine
Revenue by major product
Net premiums earned	13,544,000	11,891,000	38,865,000	35,119,000
Property | Crop reinsurance
Revenue by major product
Net premiums earned	14,873,000	11,478,000	22,207,000	17,478,000
Property | Property reinsurance
Revenue by major product
Net premiums earned	6,491,000	3,834,000	14,860,000	10,803,000
Property | Other property
Revenue by major product
Net premiums earned	4,023,000	2,842,000	11,189,000	8,449,000
Surety
Revenue by major product
Net premiums earned	$ 26,700,000	$ 20,483,000	$ 71,477,000	$ 58,533,000