SEGMENT INFORMATION - Summarized financial information by segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	$ 144,605	$ 133,952	$ 283,336	$ 267,032
Underwriting profit (loss)	(1,593)	(12,829)	15,491	(10,479)
Net investment income (loss)	11,441	11,076	22,647	22,931
Net realized investment gains	3,274	2,343	4,057	3,605
Other income (loss)	(512)	362	1,103	396
Interest expense	85	85	169	169
Other expenses	650	597	1,317	1,125
Income before income tax expense (benefit)	11,875	270	41,812	15,159
Reconciliation of assets from segment to consolidated
Assets	2,029,576		2,029,576		$ 1,994,576
Eliminations	(506,443)		(506,443)		(495,288)
Reclassifications	(3,063)		(3,063)		(1,468)
Total assets	1,520,070		1,520,070		1,497,820
Property and casualty insurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	111,254	103,517	219,459	204,764
Underwriting profit (loss)	(6,512)	(10,979)	7,566	(11,454)
Net investment income (loss)	8,150	7,972	16,176	16,588
Net realized investment gains	2,277	1,568	2,977	2,579
Other income (loss)	190	181	372	382
Interest expense	85	85	169	169
Other expenses	166	234	372	408
Income before income tax expense (benefit)	3,854	(1,577)	26,550	7,518
Reconciliation of assets from segment to consolidated
Assets	1,079,153		1,079,153		1,057,429
Eliminations	0		0		0
Reclassifications	0		0		(909)
Total assets	1,079,153		1,079,153		1,056,520
Reinsurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned	33,351	30,435	63,877	62,268
Underwriting profit (loss)	4,919	(1,850)	7,925	975
Net investment income (loss)	3,294	3,106	6,478	6,349
Net realized investment gains	997	775	1,080	1,026
Other income (loss)	(702)	181	731	14
Interest expense	0	0	0	0
Other expenses	0	0	0	0
Income before income tax expense (benefit)	8,508	2,212	16,214	8,364
Reconciliation of assets from segment to consolidated
Assets	434,675		434,675		434,139
Eliminations	0		0		0
Reclassifications	(2,171)		(2,171)		0
Total assets	432,504		432,504		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)	(3)	(2)	(7)	(6)
Net realized investment gains	0	0	0	0
Other income (loss)	0	0	0	0
Interest expense	0	0	0	0
Other expenses	484	363	945	717
Income before income tax expense (benefit)	(487)	$ (365)	(952)	$ (723)
Reconciliation of assets from segment to consolidated
Assets	515,748		515,748		503,008
Eliminations	(506,443)		(506,443)		(495,288)
Reclassifications	(892)		(892)		(559)
Total assets	$ 8,413		$ 8,413		$ 7,161