Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	$ 19,193	$ 20,366	$ 20,746
Future Policy Benefits, Losses, Claims and Loss Adjustment Expenses	481,567	450,878	415,135
Unearned Premiums	241,254	216,407	196,826
Premium Revenue	353,370	349,081	321,217
Net Investment Income	16,342	13,969	12,383
Benefits Claims, Losses and Settlement Expenses	253,688	230,149	210,055
Amortization of Deferred Policy Acquisition Costs	39,076	32,674	40,890
Other Operating Expenses	105,596	103,614	99,586
Net Premiums Written	361,829	356,944	324,352
Specialty Commercial Segment [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	11,961	13,501	14,125
Future Policy Benefits, Losses, Claims and Loss Adjustment Expenses	358,961	314,975	275,868
Unearned Premiums	185,634	161,730	146,521
Premium Revenue	241,890	237,640	228,823
Net Investment Income	12,962	11,524	12,643
Benefits Claims, Losses and Settlement Expenses	169,125	148,664	149,961
Amortization of Deferred Policy Acquisition Costs	27,474	23,371	28,186
Other Operating Expenses	58,678	58,212	53,851
Net Premiums Written	249,072	241,775	230,638
Standard Commercial Segment [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	5,849	5,633	5,892
Future Policy Benefits, Losses, Claims and Loss Adjustment Expenses	93,793	105,971	109,672
Unearned Premiums	34,334	33,701	34,822
Premium Revenue	67,510	72,613	78,311
Net Investment Income	3,471	3,623	4,663
Benefits Claims, Losses and Settlement Expenses	41,173	47,071	51,130
Amortization of Deferred Policy Acquisition Costs	12,199	4,237	3,389
Other Operating Expenses	22,117	22,820	25,479
Net Premiums Written	68,490	71,097	76,912
Personal Segment [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	1,383	1,232	729
Future Policy Benefits, Losses, Claims and Loss Adjustment Expenses	28,813	29,932	29,595
Unearned Premiums	21,286	20,976	15,483
Premium Revenue	43,970	38,828	14,083
Net Investment Income	1,276	1,235	1,633
Benefits Claims, Losses and Settlement Expenses	43,390	34,414	8,964
Amortization of Deferred Policy Acquisition Costs	(597)	5,066	9,315
Other Operating Expenses	13,119	12,205	9,977
Net Premiums Written	44,267	44,072	16,802
Corporate [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net Investment Income, Corporate	(1,367)	(2,413)	(6,556)
Other Operating Expenses	$ 11,682	$ 10,377	$ 10,279