Acquisition and Discontinued Operations Assets and liabilities of Mendota are presented as held for sale in the consolidated balance sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fixed maturities, at fair value (amortized cost of $11,316 and $14,707, respectively)	$ 11,076		$ 14,541
Equity investments, at fair value (cost of $2,052 and $4,868, respectively)	1,577		4,589
Investments	68,277		79,839
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents			23,512			$ 4,524
Accrued investment income	359		507
Other receivables, net of allowance for doubtful accounts of zero and zero, respectively	8,986		7,247
Deferred acquisition costs, net	6,899	$ 6,662	6,325	$ 6,241	$ 6,054	$ 5,827
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	138		222
Disposal Group, Including Discontinued Operation, Intangible Assets	0		7,553
Disposal Group, Including Discontinued Operation, Other Assets, Current	26,253		407
Assets held for sale	112,034		110,145
Unpaid loss and loss adjustment expenses	2,292		1,329	$ 1,494
Reinsurance Payable	15,425		82
Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities	4,160		5,223
Liabilities held for sale	107,076		105,900
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fixed maturities, at fair value (amortized cost of $11,316 and $14,707, respectively)	40,910		38,673
Equity investments, at fair value (cost of $2,052 and $4,868, respectively)	0		4,405
Investments	40,910		43,078
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	18,112		23,512
Accrued investment income	247		195
Premiums Receivable, Net	25,243		27,855
Other receivables, net of allowance for doubtful accounts of zero and zero, respectively	1		603
Deferred acquisition costs, net	1,130		6,720
Unpaid loss and loss adjustment expenses	56,332		62,323
Unearned Premiums	31,159		36,686
Disposal Group, Including Discontinued Operation, Accrued Income Tax Payable, Current	$ 0		$ 1,586