OPERATING SEGMENT INFORMATION (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenue by major product
Net premiums earned	$ 130,826,000	$ 121,758,000	$ 246,877,000	$ 238,022,000
Casualty
Revenue by major product
Net premiums earned	58,332,000	58,640,000	113,311,000	118,006,000
Increase (decrease) in segment revenue due to reclassification of business division			300,000
Increase (decrease) in net earnings due to reclassification of business division			(600,000)
Casualty | General Liability
Revenue by major product
Net premiums earned	21,160,000	24,799,000	43,124,000	49,779,000
Casualty | Commercial and personal umbrella
Revenue by major product
Net premiums earned	15,713,000	15,298,000	31,285,000	30,494,000
Casualty | Commercial transportation
Revenue by major product
Net premiums earned	8,604,000	10,356,000	17,517,000	20,783,000
Casualty | Executive products
Revenue by major product
Net premiums earned	4,336,000	3,766,000	8,558,000	7,737,000
Casualty | Specialty programs
Revenue by major product
Net premiums earned	1,089,000	1,816,000	2,429,000	4,113,000
Casualty | P&C package business
Revenue by major product
Net premiums earned	4,109,000		4,109,000
Casualty | Professional services
Revenue by major product
Net premiums earned	1,899,000	904,000	3,388,000	1,584,000
Casualty | Other
Revenue by major product
Net premiums earned	1,422,000	1,701,000	2,901,000	3,516,000
Property
Revenue by major product
Net premiums earned	47,963,000	43,644,000	88,789,000	81,966,000
Property | Commercial property
Revenue by major product
Net premiums earned	20,386,000	20,130,000	40,599,000	40,162,000
Property | Marine
Revenue by major product
Net premiums earned	12,849,000	12,060,000	25,321,000	23,228,000
Property | Crop reinsurance
Revenue by major product
Net premiums earned	6,262,000	5,109,000	7,334,000	6,000,000
Property | Property reinsurance
Revenue by major product
Net premiums earned	4,580,000	3,549,000	8,369,000	6,969,000
Property | Other property
Revenue by major product
Net premiums earned	3,886,000	2,796,000	7,166,000	5,607,000
Surety
Revenue by major product
Net premiums earned	$ 24,531,000	$ 19,474,000	$ 44,777,000	$ 38,050,000