SEGMENT INFORMATION - Summarized financial information by segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	$ 145,788	$ 138,316	$ 429,124	$ 405,348
Underwriting profit (loss)	(2,636)	(9,788)	12,855	(20,267)
Net investment income (loss)	11,299	11,503	33,946	34,434
Net realized investment gains (losses)	7,498	(390)	11,555	3,215
Other income	519	1,230	1,622	1,626
Interest expense	84	84	253	253
Other expenses	675	588	1,992	1,713
Income before income tax expense (benefit)	15,921	1,883	57,733	17,042
Reconciliation of assets from segment to consolidated
Assets	2,064,882		2,064,882		$ 1,994,576
Eliminations	(508,553)		(508,553)		(495,288)
Reclassifications	(804)		(804)		(1,468)
Total assets	1,555,525		1,555,525		1,497,820
Property and casualty insurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	113,753	107,952	333,212	312,716
Underwriting profit (loss)	(101)	(4,414)	7,465	(15,868)
Net investment income (loss)	8,125	8,230	24,301	24,818
Net realized investment gains (losses)	4,889	(286)	7,866	2,293
Other income	210	202	582	584
Interest expense	84	84	253	253
Other expenses	196	132	568	540
Income before income tax expense (benefit)	12,843	3,516	39,393	11,034
Reconciliation of assets from segment to consolidated
Assets	1,108,180		1,108,180		1,057,429
Eliminations	0		0		0
Reclassifications	0		0		(909)
Total assets	1,108,180		1,108,180		1,056,520
Reinsurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	32,035	30,364	95,912	92,632
Underwriting profit (loss)	(2,535)	(5,374)	5,390	(4,399)
Net investment income (loss)	3,176	3,275	9,654	9,624
Net realized investment gains (losses)	2,609	(104)	3,689	922
Other income	309	1,028	1,040	1,042
Interest expense	0	0	0	0
Other expenses	0	0	0	0
Income before income tax expense (benefit)	3,559	(1,175)	19,773	7,189
Reconciliation of assets from segment to consolidated
Assets	436,681		436,681		434,139
Eliminations	0		0		0
Reclassifications	0		0		0
Total assets	436,681		436,681		434,139
Parent company [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	0	0	0	0
Underwriting profit (loss)	0	0	0	0
Net investment income (loss)	(2)	(2)	(9)	(8)
Net realized investment gains (losses)	0	0	0	0
Other income	0	0	0	0
Interest expense	0	0	0	0
Other expenses	479	456	1,424	1,173
Income before income tax expense (benefit)	(481)	$ (458)	(1,433)	$ (1,181)
Reconciliation of assets from segment to consolidated
Assets	520,021		520,021		503,008
Eliminations	(508,553)		(508,553)		(495,288)
Reclassifications	(804)		(804)		(559)
Total assets	$ 10,664		$ 10,664		$ 7,161