Nature of Operations and Basis of Presentation (Narrative) (Details)		3 Months Ended
	Sep. 17, 2017 segment	Mar. 31, 2018 USD ($) segment state	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment	2	1
Payment for income taxes		$ 19,000	$ 9,000
Federal tax refund received		1,503,000	0
Interest payments		0	0
Decrease in DAC asset related to assumed realization of unrealized gains (losses)		0		$ 6,294,000
Federal income tax expense (benefit)		1,209,000	4,422,000
Liability for unrecognized tax benefits		0		0
Accumulated other comprehensive income, net of tax		(55,867,000)		168,314,000
Retained earnings		$ 832,031,000		608,700,000
Future minimum lease payments due				$ 22,500,000
Future minimum payments due as a percentage of total assets				1.00%
Property and Casualty Insurance
Segment Reporting Information [Line Items]
Number of states in which we are licensed as insurer | state		46
Continuing and Discontinuing Operations
Segment Reporting Information [Line Items]
Federal income tax expense (benefit)		$ 9,316,000	$ 5,153,000
Accounting Standards Update 2016-01
Segment Reporting Information [Line Items]
Accumulated other comprehensive income, net of tax				$ (191,200,000)
Net realized investment losses		$ 8,100,000
Retained earnings				$ 191,200,000