SCHEDULE III - SUPPLEMENTARY INSURANCE INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplementary Insurance Information by Segment [Abstract]
Net Premiums Earned	$ 776,015	$ 742,040	$ 756,078
Net Investment Income	31,126	29,504	29,515
Net Losses and Loss Expenses	520,710	459,764	506,388
Amortization of Deferred Policy Acquisition Costs	128,733	119,072	122,443
Other Underwriting Expenses	129,368	125,863	114,562
Net Premiums Written	804,267	742,140	752,601
Deferred Policy Acquisition Costs	68,028	59,157
Liability For Losses and Loss Expenses	1,077,620	962,007
Unearned Premiums	572,958	537,190
Other Policy Claims and Benefits Payable	0	0
Commercial Lines [Member]
Supplementary Insurance Information by Segment [Abstract]
Net Premiums Earned	468,433	412,877	385,465
Net Investment Income	0	0	0
Net Losses and Loss Expenses	321,483	264,053	242,685
Amortization of Deferred Policy Acquisition Costs	84,927	66,253	62,424
Other Underwriting Expenses	85,345	72,245	61,631
Net Premiums Written	501,785	425,986	404,879
Deferred Policy Acquisition Costs	41,225	33,246
Liability For Losses and Loss Expenses	814,681	694,569
Unearned Premiums	347,213	301,901
Other Policy Claims and Benefits Payable	0	0
Personal Lines [Member]
Supplementary Insurance Information by Segment [Abstract]
Net Premiums Earned	307,582	329,163	370,613
Net Investment Income	0	0	0
Net Losses and Loss Expenses	199,227	195,711	263,703
Amortization of Deferred Policy Acquisition Costs	43,806	52,819	60,019
Other Underwriting Expenses	44,023	53,618	52,931
Net Premiums Written	302,482	316,154	347,722
Deferred Policy Acquisition Costs	26,803	25,911
Liability For Losses and Loss Expenses	262,939	267,438
Unearned Premiums	225,745	235,289
Other Policy Claims and Benefits Payable	0	0
Investments [Member]
Supplementary Insurance Information by Segment [Abstract]
Net Premiums Earned	0	0	0
Net Investment Income	31,126	29,504	29,515
Net Losses and Loss Expenses	0	0	0
Amortization of Deferred Policy Acquisition Costs	0	0	0
Other Underwriting Expenses	0	0	0
Net Premiums Written	0	0	$ 0
Deferred Policy Acquisition Costs	0	0
Liability For Losses and Loss Expenses	0	0
Unearned Premiums	0	0
Other Policy Claims and Benefits Payable	$ 0	$ 0