Acquisition and Discontinued Operations Mendota and Mendakota Insurance Company Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2018	Jun. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation	$ 0	$ 0			$ 0	$ 0
Disposal Group, Including Discontinued Operation, Revenue	25,571	36,721			56,874	72,455
Net Investment Income	1,010	864			1,648	2,032
Net realized gains (losses)	132	(1)			397	(1)
(Loss) gain on change in fair value of equity investments	(421)	0			744	0
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	28,900				28,900
Liability for Unpaid Claims and Claims Adjustment Expense, Reported Claims, Amount	2,500				2,500
Disposal Group, Including Discontinued Operation, Other Income	2,445	2,556			4,876	5,027
Loss and loss adjustment expenses	1,301				1,647
Disposal Group, Including Discontinued Operation, Other Expense	2,225	5,353			6,388	10,636
Disposal Group, Including Discontinued Operation, General and Administrative Expense	3,825	4,880			7,778	10,430
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0	0			0	250
Disposal Group, Including Discontinued Operation, Operating Expense	24,977	36,363			55,894	72,637
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	594	358			980	(182)
Discontinued Operation, Tax Effect of Discontinued Operation	0	0			0	(85)
Income (loss) from discontinued operations, net of taxes	594	358		$ 358	980	(97)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(6,628)	1,017			(6,628)	1,017
(Loss) gain on disposal of discontinued operations, net of taxes	(6,628)	1,017	$ 1,017		(6,628)	1,017
Operating Income (Loss) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue	22,956	33,518			51,592	66,440
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Investment Income	208	(88)			434	(145)
Net realized gains (losses)	(134)	735			(134)	1,133
(Loss) gain on change in fair value of equity investments	96	0			106	0
Loss and loss adjustment expenses	18,927	26,130			41,728	51,321
(Loss) gain on disposal of discontinued operations, net of taxes	1,335
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) gain on disposal of discontinued operations, net of taxes	(6,034)	$ 1,375			$ (5,648)	$ 920
Other Segments [Member] | Sale of Subsidiary Gain (Loss) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) gain on disposal of discontinued operations, net of taxes	$ (7,964)